US3300821A

US3300821A - Battery grid casting method and machine

Info

Publication number: US3300821A
Application number: US389564A
Authority: US
Inventors: Charles A Nichols; Alexander H Joyce; Charles W Gardner; William A Fletcher
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1964-08-14
Filing date: 1964-08-14
Publication date: 1967-01-31
Anticipated expiration: 1984-01-31

Description

Jan. 31, 1967 c. A. NICHOLS ET AL I 3,300,821

BATTERY GRID CASTING METHOD AND MACHINE Filed Aug. 14, 1964 4 Sheets5heet l I .7? w a,

INVENTORS I Char) 0. ??z'c)1o)s THEIR ATTORNEY c. A. NICHOLS T AL 3,300,821

BATTERY GRID CASTING METHOD AND MACHINE Jan. 31, 1967 Filed Aug. 14, 1964 r 4 Sheets-Sheet 2 QUE: 'UQEJWWEWH [3cm EIIEFTLJ u m E QLEEUEE QQQQGEQQ QQUQGQQQ Hmmm INVENTORS 522W) 0. ?72'c)2o)s CZ/exander 1'2. Jgyce Cbafles Z11 ara'ner THE/R AT7-ORNE Y Jan. 31, 1967 c. A. NICHOLS ET AL 3,300,821

BATTERY GRID CASTING METHOD AND MACHINE Filed Aug. 14, 1964 4 Sheets-Sheet 3 INVENTORS ()mrdes Q Wickds a/azazzdar 19. Jgyce C/ 'az'ks M ara'zzer A /[Dian Q fiafc'fiaz 1967 c. A. NICHOLS ET AL 3,300,821

BATTERY GRID CASTING METHOD AND MACHINE Filed Aug. 14 1964 4 Sheets-Sheet 4 UV VEN TOR 5 (War/es 0 Widw); Ukxande) 19. Jqyce Ckaflas' 'ardxer M1114; Q Ha e-22a) 7715/)? A7 TORNEY United States Patent 3,300,821 BATTERY GRID CASTING METHOD AND MACHINE Charles A. Nichols, Largo, Fla., and Alexander H. Joyce, Detroit, Charles W. Gardner, Oxford, and William A. Fletcher, Bloomfield Hills, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Aug. 14, 1964, Ser. No. 389,564 9 Claims. (Cl; 22-574) This invention relates to an improved machine and method for continuously casting strips of battery grids from molten material.

While machines for continuously manufacturing strips of material or castings from a molten mass are known, none of these machines or methods has been completely suitable for casting articles having close tolerance components or small dimension, for example, a battery grid having grid wires directed between crossbars enclosed by a rim or peripheral bead on the outer periphery of the grid. In casting articles of this type by a continuous process, it has been found that presently known machines are unable to completely assure good reproduction of the mold configuration because of problems in completely filling the mold and extracting the casting therefrom.

Accordingly, an object of the present invention is to provide an improved method for manufacturing continuous strip castings including a high-low principle of molding wherein a first portion of the mold is made of a material having a low diffusivity factor for preventing solidification ofrnolten material before the mold has been completely filled and a second portion of a high diffusivity factor for reducing the surface tension of the molten material to assure accurate reproduction of the mold contour in the fine detailed portions thereof.

A further object of the present invention is to improve machines for continuously manufacturing castings as a continuous strip from a mass of molten material of the type including a rotary drum mold, a dispenser, and a belt by the provision of improved means for locating the dispenser in close tolerance relationship ,with the mold and a floating roll that compensates for drum eccentricity to maintain a substantially constant geometry between roll and mold as molten material flows from the dispenser into the juncture between the mold and roll whereby an even distribution of molten material into the mold is obtained while preventing flashing across the mold face to assure complete reproduction of the mold contour. I i

A further object of the present invention is to improve the manufacture of battery grids or the like in machines of the above-described type by an improved continuously flowing stream of molten material to and from a pool for filling a continuously advancing mold surface. 7

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a diagrammatic view of a process line including the continuous casting machine and method of the present invention;

FIGURE 2 is a view in side elevation of the present invention;

FIGURE 3 is a fragmentary view partially in side elevation and in section showing the dispenser, floating roll, drum mold and belt relationship in the improved machine;

FIGURE 4 is a plan view looking in the direction of arrows 4-4 in FIGURE 2;

aaaaszi Patented Jan. 31 1967 FIGURE 5 is a reduced view in vertical section taken substantially along the line 55 of FIGURE 3 including a showing of means for raising and lowering the dispenser; v V V i Y FIGURE 6 is a fragmentary, enlarged view in vertical section taken along the line 66 of FIGURE 2;

FIGURE 7 is an enlarged, fragmentary view in vertical sectionof a further embodiment of a drum mold surfacejand FIGURE 8 is an enlarged, fragmentary view in vertical section of another embodiment of a mold of the present invention.

Referring now to FIGURE 1 of the present invention, a process line for continuously manufacturing strip castings, for example, castings of battery grids or the like, is illustrated as comprising a melting system 10 for directing molten material, for example, an antimony lead alloy to a casting machine 12'and thence through a trim station 14 for trimming the casting and thence through a paste station 16 for filling the voids in the battery grid castings with a suitable electrochemically active material, and thence through a shear station 18 for separating the continuous strip of battery grids into individ ual units. These units are then passed through a suitable oven 20 for curing the active material in the grid framework and thence to a secondary shear station 22 for further separating the finally cured battery grids into battery size units which are then carried to a suitable assembling station by means of a conveyor belt 24.

The continuous grid casting machine 12 is best illustrated in FIGURE 2 as comprising a large diameter mold drum 26 having an outer peripheral flange portion 28 supported by a radially inwardly.directed web or disc 30 supportingly received on a drum adapter unit or element 32 having a plate portion 34 securedto the-Web 30 by suitable fastening means, such as a key. In the illustrated embodiment, a key element (not shown) is located in engagement between the web 30 and plate ,34 to prevent relative movement between the drum 26. and the adapter unit. A shaft 40 secured to the adapter is rotatably supported upon suitable fixed framework 42 whereby the mold drum 26 is rotated about the axis of shaft 40 by suitable drive means (not shown) acting through shaft 40. The outer periphery of the mold drum 26 will thus drivingly engage a continuous belt 44 that 7 passes about a pulley,.45 rotatably supported on the fixed support 42 by means of a shaft 46 and thence across .a

belt tension roller 48 rotatably supported on a movable plate 50 that is biased so as to produce a predetermined pressure between roller 48 and belt 44 by a spring loading device 52 including a threaded stud 53 received by a fixed bracket 54 for adjusted movement therein so as to vary the spring force of a coil spring 55 in surrounding relationship with one end of stud 53. Following passage over the belt tension roller 48, belt 44 passes over spaced

rollers

56, 58 located thereabove to guide the belt 44 in a substantially vertical direction prior to its passage over an equalizing roller 60. As best seen in FIGURES 2 and 5 the roller 60 is supported at each of its ends on one end of each of a pair of equalizing arms 62 each having a downwardly curving upper portion 63 thereof pivotally supported on a pin 64 supported by the fixed support 42. The opposite end or offset portion 65 on each arm 62 depends substantially in a vertical plane and supports suitable counterweights 66 that tend to. pivot the roller 60 about the axis of pin 64 toward the outer periphery of the drum 26 where the belt 44 cooper-. ates with drum '26 to form a throat region 68 therebetween as it passes from the'roller 60 onto the drum 26.

The continuous belt 44 then passes about the drum 26 v through less than of the outer circumference thereof to return to the idler pulley 45 from whence the continu 3 ously cast grid strip is directed to a further processing step, for example, to the trip stage 14 illustrated in FIG- URE 1. In order to produce the continuous strip of casting from a source of molten material, the belt 44 is preferably constructed of a high temperature resistant material of substantial flexibility, for example, a special silicone rubber, 4-ply belt with a No. 8025 fabric material as manufactured by Goodyear Tire and Rubber Company. This material was used on one working etnbodiment of the machine and in addition to having desired thermal durability, it had an outer surface of approximately six-ty durometers in order to produce castings of good quality.

Previous to the present invention, it was recognized that continuous strips might be continuously cast from a mass of molten material; however, previous machines are limited to casting articles wherein the component parts thereof have substantial dimensions without close tolerances. When the mold configurations of previous machines are modified to include small dimensional characteristics and fine detailed portions that must be continuously manufactured to very close tolerances, it has been found .thatportions of the mold fail to fill and, hence, there is not a reliable continuous reproducibility of mold configurations and/or there is an overfilling of the mold with a considerable flashing of excess material across the mold surface that renders the finished casting completely unsuitable for its intended purpose.

In the illustrated embodiment of the invention, a molten material is fed into the throat region 68 between belt 44 and drum 26 in a manner and under a temperature control that assuresthat a continuous strip of substantially identical castings of desirable tolerance will be directed from the drum 26.

In accordance with certain of the principles of the present invention, improved means are included in the illustrated casting machine 12 to uniformly direct a predetermined amount of molten material at'a desired fluidity into a mold cavity on the drum 26 that is representativelyillustrated in FIGURE 4 as including a battery grid 70 having small cross-sectioned grid wire depressions 72 extending between larger cross-sectioned cross-arm depressions 74 each being connected at the outer ends thereof to a relatively large cross-section rim depression 76 having a tab portion 78 integrally formed therewith.

More particularly, in the illustrated embodiment of the present invention, as best seen in FIGURE 3, the equalizing roller 60 cooperates with the belt 44 in the vicinity of the throat region 68 to fulfill three important functions in maintaining a throat region of constant geometry. One of these functions is that the two independent pivoted equalizing arms 62 and self-aligning bearings at the ends of the shaft or roller 60 allow the equalizing roller 60 to shift relative to the outer periphery of the drum 26 to compensate for eccentricity or wobble'therein. e

Furthermore, by adjusting the counterweights 66, it is possible to apply equal force to each end of the equalizing roller 60 whereby a uniform contact pressure between the belt 44 and the drum 26 is attained across the entire width of the throat region 68. By virtue of the equalizing roller system, any variation in the diameter of the drum due to thermal expansion is compensated for by pivotal movement of the roller 60 arouhd the pin 64 by an amount equivalent to the thermal expansion in drum 26 whereby the contact pressure between the belt 44 and drum 26 is maintained substantially constant. Y

By virtue of the above-described characteristics "of the equalizing roller system, the throat region 68 is maintained substantially geometrically constant and, accordingly, molten material directed therein can be controlled to produce a closely controlled filling of the continuous mold on the outer periphery of drum 216. In the illus;

trated embodiment of the invention, as best seen in FIG- URES l-3, molten material is fed into the throat region 68 from the source 10 of molten material that is representatively illustrated as including a lead pot having a predetermined charge of molten material therein that is circulated by a pump 82 through a discharge conduit 84 connected to a three-way control valve 86 that directs the molten material through a conduit 88 connected thereto that has one end thereof connected to a fitting 90 serving as a support for a thermocouple unit in a thermo- Well 167 thereon. From valve 86 a recirculating conduit 94 directs fluid from discharge conduit 84 in bypassed relationship to the dispenser assembly 92 during certain phases of the operation of the illustrated casting machine 12.

The dispenser assembly 92 is connected to the fitting 90 by a line 96 through a centrally located inlet opening 98 on the rear face of a wedge-shaped head portion 100. Interiorly of the wedge-shaped head portion 100 is a centrally located downwardly directed opening 104 that directs molten fluid to a narrow tip portion 106 of head 100 that overlies the juncture between the belt 44 and mold drum 26. When the three-Way valve is conditioned to direct molten fluid from the discharge conduit 84 to the fitting 90, a continuous flow of molten material is directed through the distributor opening 104 into the throat region 68 where the belt and drum serve to divide the molten stream issuing from the distributor opening 104 into substantially equal divided streams that pass transversely across the face of the continuously advancing mold 70 on the outer periphery of the drum 26 through substantially half the width of the advancing mold.

As the stream of continuous molten material passes across such equal portions on the face of the advancing mold, the'belt 44 'is continuously acted upon by the equalizing roller 60 to Wipe a predetermined portion of the continuously circulating molten material into the cavities of the advancing mold with a continuously uniform pressure across the Width of the mold sufficient to assure that the molten material will fill even relatively small dimensional portions of the mold cavity, for example, the small wire portions '72 therein. As best seen in FIGURE 5, any matter in excess of that required to fill the cavity portions of the continuously advancing mold flows 'exteriorly of the side edges of the outer periphery of the belt 44 and drum 26 where it is received by

funnels

108, 110 located on either side thereof with each of the

funnels

168, 110 communicating with a like conduit 112 serving to return the excessive material or overflow to the lead pot 80 for recirculation back to the dispenser assembly 92. 2

Another feature of the present invention is the fact that the illustrated dispenser assembly 92 serves to prevent leakage of the molten material exteriorly of the throat region 68 other than through the open sides thereof into the

funnels

108, 110. In order to assure against leakage other than through such side openings, the wedge-shaped head 10% is carefully spotted between the continuous belt 44 and the other periphery of the drum 26 so that arear surface 114 thereon having a curvature corresponding substantially to that of the equalizing roller 160 serves to slidably direct the belt 44 into a tangential relationship with the outer surface of drum 26 and prevent leakage rearwardly of the throat region 68. A front surface 116 on head 100 having a curvature substantially corresponding to that of the outer periphery of drum 26 serves as a front locator against the drum and to seal between the front of dispenser assembly 92 and drum 26. A desired location of the Wedge-shaped head 100, belt 44 and drum 26 is obtained in the illustrated embodiment of the invention by two

toggle mechanism

118, 120 for adjusting the Wedge-shaped head both vertically and horizontally with respect to the throat region 68. The

toggles

118, 12! are each conventional arrangements that perform the dual .5 functions of following a predetermined adjusting motion to a locked position. In the illustrated arrangement these toggles serve as a means for obtaining a rough location of head 100 with respect to drum 26 and belt 44. Fine adjustment of head 100 is obtained by adjustment means including a fiat plate portion 130 supported by suitable means on the fixed framework 42. The plate 130 threadably supports a pair of spaced

screws

132, 134 that depend therefrom through elongated membersor guide

sleeves

136, 138 respectively. Each of the

screws

132, 134 has a bifurcated end 139 thereon that is pivotally connected to a lug 140 on the side of the head 100 by a pin 141. Each of the

screws

132, 134 also has a spring 142 located therearound held between a depending part on the plate 130 and the

members

136, 138 to bias the wedge-shaped head 160 away from the plate 130 to produce a desired vertical spacing of the tip 106 within the throat region 68. A continuous chain 156 rides over

sprockets

160, 162 secured to the upper end of each

screw

132, 134, respectiveiy, whereby, upon adjustment of one of the screws, the chain 150 and

sprockets

160, 162 conjointly move and the

screws

132, 134 are closely adjusted equally in the vertical with respect to the flat plate portion 130 for changing the relationship between head 100, belt 44 and drum 26. I

Accordingly, the dispenser head 100 can be closely adjusted to its operating position where it is spotted within the throat region 68 so that the concave rearward surface 114 and the forward surface 116 thereon will be in juxtaposition with the belt 44 and drum 26, respectively. By virtue of the above-described adjusting mechanism, when it is desired to move the dispenser 92 exteriorly of the throat region 68, it is merely necessary to release the

toggle mechanisms

118, 120.

During the casting of molten material into the molds on drum 26, temperature control of various portions of the device are fairly critical. For example, if the tem perature is too high at the dispenser, molten lead or the like may fountain up between the interface between dispenser head 100, belt 44 and drum 26 or if the temperature is too low, the molten material may tend to solidify in the dispenser to restrict the continuous circulation of molten material transversely of the continuously advancing mold face. One representative thermal control arrangement includes thermal couple controlled cartridge heaters 164 having 400 watts at 115 volts located within openings 166 on either side of the head 100. These heaters, under the control of thermocouples in thermowells 167, maintain the material at approximately 600 F. when the initial temperature in the pct 80 is around 830 F. Under these circumstances, the drum 26 is preferably controlled at about 280 F. During casting of grids within the mold on the outer periphery of drum 26, the web 30 of the drum is cooled to prevent the drum temperature from rising above the desired control range. In the illustrated embodiment of the invention, as shown in FIGURE 6, cooling is accomplished by spraying the web 30 with water from a spray gun apparatus 168. The spray is controlled by a control pyrometer assembly 170 that measures the temperature of the inside surf-ace of the drum through a surface mirror 172 that reflects.

It has been found that in some cases when the tem perature control was maintained solely on the drum 26, the grid surface cast against the belt 44 had a coarse grained structure. Accordingly, in certain cases, it may be desirable to also control the temperature of the belt by means similar to that used on the drum to obtain desired grain size characteristics on the belt side of the grids.

The continuous flow of molten material through the throat region 68 desirably takes place within a throat region having a maximum volume with a minimum area of contact with the drum and belt to assure that the belt will form relatively flash-free accurate grids on the outer periphery of drum 26. In order to obtain maximum volume with a minimum area of contact, the throat should have a cross section as close as is feasible to an equilateral triangle. In addition to the geometric configuration of the throat area, other aspects of the invention assure that lead will completely fill the mold cavities and that excess molten material will return to the melting pot for reheating. Among these additional factors are (l) a large excess of lead is directed by the pump 82 through the throat region to produce a sufiiciently high velocity to prevent the circulating stream from solidifying; (2) the belt is constructed from a low-heat conductive material to minimize the temperature drop of the lead stream in the throat region; (3) the mold drum is hard coat anodized at the outer surface or mold area in rim 28. Such an anodized coat has a low diffusivity of heat that minimizes the temperature drop of the lead stream on initial contact with the drum. In the illustrated machine the anodized coat is a BOSS-.004" insulation layer that has been sprayed with a very thin layer of a suitable break-in compound. For purposes of this specification, diffusivity refers to thermal conductivity di vided by volumetric heat capacity.

Once a portion of the fluid lead stream has been wiped into the mold cavities by the belt 44 and the excess has flowed through the side openings into

funnels

108, 110, the belt is driven along with the drum 26 to trap the molten material in the mold cavities for a predetermined period of time that enables the drum web 30 which has a high heat diffusivity and is constructed, for example, of aluminum to quench the grids while maintaining as uniform a temperature as possible across the mold surface by controlled heating thereof through a like pair of burners 174, 176 located in proximity to the drum,

26 on either side thereof. The burners serve primarily to preheat the drum 26 to the desired drum casting temperature at which timethe circulating ead stream will maintain the temperature of the drum under control of the cooling spray gun 168. A third burner pair 177, impinges on the return lines 112 to prevent solidification of the molten material therein.

Another aspect of starting the illustrated machine is that during initial startup, there might be a tendency for, excessive flash to form on the surface of the drum. Ac-. cordingly, a skiver apparatus 178 is supported over plate above drum 26 so that a blade portion 180 is located tangent to the diameter of the outer drum with the leading edge thereof closely adjacent on the vertical center line of the drum. The skiver apparatus includes suitable means for adjusting the leading edge of blade 180 so that it will not cut into the surface of the drum while removing excessive flash from the outer periphery thereof.

In summary, the improved method for continuously casting strips of articles having close dimensional tolerances is made possible by passing a continuous stream'of molten material tangentially to a continuously advancin rotary mold surface while wiping a predetermined portion of the continuously circulating stream into the mold cav-. ity without materially reducing the temperature of the molten fluid stream below a desired temperature so as to maintain a desired fluidity. One working embodiment of a machine of the type discussed above successfully continuously casts battery grids from a lead alloy containing between 4% and 7% antimonial lead where the variations in liquid temperature produced by the difference in antimony in the alloy are compensated for by suitable changes in the drum temperature and temperature of the lead supply in pot 80.

The method also contemplates the application of a uniform pressure upon the continuously circulated stream of molten material as it is being wiped into the rotary mold. For example, in the above illustrated machine, the equalizing roller produces the desired substantially constant pressure across the mold surface for wiping the desired portion of the stream of material therein. The

fact that the belt and outer surface of the drum are of low conductivity material combines with the heating of the pool within throat region 68 to maintain the desired fluidity of the material as it is initially being cast into place. The fact that an excessive amount of material is circulated aids in maintaining a desired fluidity because the fluid stream passes at a relatively high velocity across the throat region during the casting process.

Furthermore, in the illustrated machine the method of quickly quenching the mold is carried out by the fact that the drum interior serves as a substantial heat sink of high-heat conductivity material closely adjacent the low-heat conductivity mold cavities of low diffusivity. The relationship of high and low heat diffusivity regions can be referred to as a high-low theory of castingv By virtue of this theory, it has been found that the final castings are uniformly quenched across the mold face in a relatively short period of time. Accordingly, the belt only has to pass over a portion of the drum less than 180 and because of the reduced contact between the drum and the continuous belt, the belt has improved wear characteristics.

By virtue of the above-described apparatus the casting rate can be increased or decreased by merely varying the cooling action of spray gun 168 to take care of the variation of heat input into the drum 26 produced by the operation thereof at changing speeds. Furthermore, variations in grid thickness can be easily compensated for in the illustrated machine by increasing lead supply and water flow to the spray gun to compensate for the added heat input into the system produced by the increased grid thickness. Like reductions in lead supply and cooling water how will occur for castings having smaller thicknesses.

In accordance with other concepts of the present invention, in certain cases the mold shape might be such that it is dificult to overcome the surface tension of the molten material being wiped therein by belt 44. In this case, the mold cavity has been modified to the form best illustrated in FIGURE 7 to have a layer 182 of lowthermal conductivity material that is substantially greater in thickness than the anodized surface discussed above but still of low diifusivity. Furthermore, the low-conductivity surface does not overlie all portions of the grid mold cavity. For example, in FIGURE 7, the low-conductivity material is such that the material being wiped from the throat area 68 into the outer periphery of the drum 26 is chilled at the base of depressions 72', 74 and 76' corresponding to like depressions in FIGURE 4. The drum 184 in this embodiment is of a high-conductivity material such as aluminum having high diffusivity that will rapidly chill the molten material in the bottom of the mold depressions while the remainder of the casting configuration is maintained at a higher temperature because of the low-heat diffusivity properties of the insulate ing layer 182. Because of this modified high-low principle of casting, it has been found that the'surface tension of the molten material is substantially overcome so that the molten material will substantially completely fill all portions of the grooves of the mold to assurehccurate mold reproduction. The small area of the mold that has the high-heat conductivity characteristics will not substantially raise the overall heat transfer from the pool in the vicinity of throat 68 sufficiently to make material solidification a problem prior to complete filling of the mold. This high-low principle of casting has been carried out by using a rubber insulating coat with it being understood that other suitable insulators, for example, synthetics such as epoxy resins and the like would be equally suited for practicing this aspect of the invention.

In the embodiment of FIGURE 8, the high-low principle is carried out by forming an insulating layer 186 On the outer surface of a lug 188 that is bolted to the outer rirn 190 of a rotary drum 192. In this embodiment depressions like those in FIGURES 2 6 and FIG- URE-7 are formed in the layer 186 and each lug is sealed at its end by a seal insert 194 that extends transversely across the full width of the rim 190.

While the embodiments of the apparatus of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted and furthermore, it is understood that the method may be practiced by apparatus other than that illustrated.

What is claimed is as follows:

1. A machine for continuously molding castings comprising the combination of, a rotary mold drum, a con tinuous belt, means for supporting said continuous belt with a portion thereof freely movable relative to said rotary mold drum and a second portion continuously engaging a second portion of said drum, said first portion of said continuous belt cooperating with said rotary drum to form a throat region therebetween, dispenser means located within said throat region having a portion thereof in engagement with said freely movable belt portion, means for maintaining a second portion of said dispenser means in engagement with the outer periphery of said drum, means for circulating molten material through said dispenser means into said throat region and exteriorly thereof; said freely movable belt portion being adjustably movable to compensate for variations in the diameter of the rotary drum and serving to Wipe a predetermined portion of the circulating molten material in the throat region into the outer peripheral face of the rotary mold drum, said continuous belt and rotary drum cooperating to trap the molten material in the outer periphery of the drum for a predeterminectperiod of time, said continuous belt and rotary drum having relatively low coefficients of heat diffusivity where they contact the molten material for maintaining the trapped molten material at a temperature substantially corresponding to the temperature in the throat region to assure penetration of the molten material into all parts of the mold, said continuous belt and drum serving to trap the molten material within the mold for a suflicient time to allow solidification of the material therein by heat transfer to a high-diffusivity portion of said drum.

2. In the combination of claim I, said dispenser means including means for establishing a substantially uniform, continuous how of molten material through said throat region across the full transverse extent of the outer periphery of said rotary drum. I

3. In the combination of claim 1, said dispenser means including a centrally located outlet arranged equidistantly from the side walls of said rotary drum, said continuous belt and drum cooperating with said dispenser means to direct the flow from the outlet thereof in substantially equally divided streams toward the outer side walls of the rotary drum, and further including means for retrieving excessive molten material from the throat region adjacent the side walls of the rotary mold for recirculation through the dispenser outlet.

4. In the combination of claim 1 said means for mounting said continuous belt including a roller element, self-aligning bearing means for supporting said roller for limited universal movement relative to said rotary mold drum, and means for supporting said bearing for pivotal movement relative to said rotary drum for maintaining a substantially constant belt pressure on said drum irrespective of dimensional variations therein, and means operatively associated with said pivotal support means for varying the pressure of said belt against said rotary drum.

5. The combination of claim 1, wherein the dispenser includes a first surface overlying substantially the full width of said rotary drum and having a curvature cornplementary to that of the drum through a substantial arcuate segment thereon, and further including a second surface overlying substantially the full width of the continuous belt and having a curvature directing the freely movable portion of the continuous belt substantially tangentially to the drum at the initial point of contact therewith, said dispenser further including means forming an inlet and an outlet located substantially tangentially to the outer peripheral surface of said drum for directing molten material into the throat region formed by said continuous belt and said rotary drum, and means located within said dispenser on either side of said inlet and outlet means for maintaining the molten material passing from said dispenser in a completely fluid state, means for maintaining the temperature of the material at the throat region at a molten temperature, and means for recirculating molten material from the throat region for preventing formation of flash deposits on the outer periphery of the rotary mold.

6. In the combination of claim 1, means for cooling the drum balance the input of heat thereto during the continuous processing of mold castings including means for sensing the inside surface temperature of the rim of the drum and means for directing a cooling medium against the radially inwardly located portions of the drum in response to a predetermined sensed rim temperature.

7. In the combination of claim 1, means for lifting said dispenser means into and out of said throat including a movable support member, two screws directed through said support member each having a portion thereof threadably connected to said dispenser means for threadably adjusting the spacing between said dispenser means and said support member for firmly adjustably moving said dispenser means into and exteriorly of the throat region, means for coupling said screws for conjoint adjustment for closely controlling the height of said dispenser means within the throat region, and means for vertically moving said support member to quickly move said dispenser means to and from its finely adjusted position without disturbing the fine adjustment of said dispenser means with respect to the throat region.

8. In the combination of claim 1, said rotary mold drum having an outer hard coat anodized surface for insulating against rapid solidification of molten material wiped therein to assure complete filling of all portions of the mold cavities.

9. 1n the combination of claim 1, means for removing flashing from the outer surface of said rotary mold during start-up of the machine prior to establishing a desired operating temperature in the drum and associated mold material circulation system, said drum and belt 00- operating following the attainment of such desired temperatures to continuously mold castings without building up any noticeable flashing on the outer face of the drum mold.

References Cited by the Examiner UNITED STATES PATENTS 1,507,456 9/1924 Brasted 2257.4 1,612,737 12/1926 Lane 2257.4 1,636,242 7/1927 Prachar 2257.5 X 2,128,942 9/1938 Hudson 2257.5 2,206,930 7/1940 Webster 2257.3 2,450,428 10/1948 Hazelett 2257.4 2,659,948 11/1953 Properzi 22-574 2,956,320 10/1960 Pulsifer 2257.4

FOREIGN PATENTS 861,273 2/1961 Great Britain.

1. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner.

Claims

1. A MACHINE FOR CONTINUOUSLY CASTINGS COMPRISING THE COMBINATION OF, A ROTARY MOLD DRUM, A CONTINUOUS BELT, MEANS FOR SUPPORTING SAID CONTINUOUR BELT WITH A PORTION THEREOF FREELY MOVABLE RELATIVE TO SAID ROTARY MOLD DRUM AND A SECOND PORTION CONTINUOUSLY ENGAGING A SECOND PORTION OF SAID DRUM, SAID FIRST PORTION OF SAID CONTINUOUS BELT COOPERATING WITH SAID ROTARY DRUM TO FORM A THROAT REGION THEREBETWEEN, DISPENSER MEANS LOCATED WITHIN SAID THROAT REGION HAVING A PORTION THEREOF IN ENGAGEMENT WITH SAID FREELY MOVABLE BELT PORTION, MEANS FOR MAINTAINING A SECOND PORTION OF SAID DISPENSER MEANS ION ENGAGEMENT WITH THE OUTER PERIPHERY OF SAID DRUM, MEANS FOR CIRCULATING MOLTEN MATERIAL THROUGH SAID DISPENSER MEANS INTO SAID THROAT REGION AND EXTERIORLY THEREOF; SAID FREELY MOVABLE BELT PORTION BEING ADJUSTABLY MOVABLE TO COMPENSATE FOR VARIATIONS IN THE DIAMETER OF THE ROTARY DRUM AND SERVING TO WIPE A PREDETERMINED PORTION OF THE CIRCULATING MOLTEN MATERIAL IN THE THROAT REGION INTO THE OUTER PERIPHERAL FACE OF THE ROTARY MOLD DRUM, SAID CONTINUOUS BELT AND ROTARY DRUM COOPERATING TO TRAP THE MOLTEN MATERIAL IN THE OUTER PERIPHERY OF THE DRUM FOR A PREDETERMINED PERIOD OF TIME, SAID CONTINUOUS BELT AND ROTARY DRUM HAVING RELATIVELY LOW COEFFICIENTS OF HEAT DIFFUSIVITY WHERE THEY CONTACT THE MOLTEN MATERIAL FOR MAINTAINING THE TRAPPED MOLTEN MATERIAL AT A TEMPERATURE SUBSTANTIALLY CORRESPONDING TO THE TEMPERATURE IN THE THROAT REGION TO ASSURE PENETRATION OF THE MOLTEN MATERIAL INTO ALL PARTS OF THE MOLD, SAID CONTINUOUS BELT AND DRUM SERVING TO TRAP THE MOLTEN MATERIAL WITHIN THE MOLD FOR A SUFFICIENT TIME TO ALLOW SOLIDIFICATION OF THE MATERIAL THEREIN BY HEAT TRANSFER TO A HIGH-DIFFUSIVITY PORTION OF SAID DRUM.