US2508865A

US2508865A - Metal casting mold

Info

Publication number: US2508865A
Application number: US758825A
Authority: US
Inventors: Arthur D Lund
Original assignee: Solar Corp
Current assignee: Solar Corp
Priority date: 1947-07-03
Filing date: 1947-07-03
Publication date: 1950-05-23
Anticipated expiration: 1967-05-23

Description

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METAL CASTING MOLD Filed July 3, 1947 r '3 Sheets-Sheff. 3

- HIM" abbot/MW Patented May 23,A 1950 METAL CASTING MOLD Arthur D. Lund, Minneapolis, Minn., assignor to Solar Corporation, Milwaukee, Wis., a corporation of Delaware Application July 3, 1947, Serial No. 758,825

s claims. (o1. :a2-153) This invention relates to improvements 'in metal casting molds for casting storage battery grid plates.

The molds are particularly designed for use in connection with automatic grid casting machines such as described in my cci-pending application for Grid plate casting machine, Serial No. 748,679, filed May 17th, 1947, and of which this application is a continuation in part. The present invention further has features in common with my prior Patent No. 2,194,092, issued March 19th, 1940, and reference is invited thereto for some details which will be only briey referred to herein, since they form no part of the present invention.

In such machines two molds are used and they have on their meeting surfaces the usual intaglio `or matrix indentations into which the molten metal is poured while the molds are together and which are shaped to properly form the grid plates las the metal hardens. In practice the molds are relatively movable and the metal is poured each time they come together, and as the molds are then separated the cast plates drop therefrom upon a conveyor by which they are removed fromA4 exhaust the air from the said surfaces and enable the mold to be quickly filled without the formation of any air bubbles or other imperfections in the cast plate. It may here be explained that each cast plate or panel comprises what will ultimately become two complete storage battery grids, which are united in the casting process by suitable surrounding frame parts, which at the proper 'time in the course of the manufacturing operation are trimmed off and parted to divide the grids. In accordance with my present invention,

I direct the molten metal down at the center` of the matrix surfaces so that it iiows immediately" into the portion thereof which` form the grids ices in the matrix surfaces and flll them com-A pletely and form perfect grids. I y

Another object of my invention is to generally improve -mold structures of this kind and to bring, about certain advantages which will be described in more detail in the course of the following specications, wherein reference is had to the accom panying drawings in which- Fig. 1 is a face view of a mold embodying my invention and showing the matrix `surfacesl stripping the plates from the molds as theyf separate. This view is taken substantially alongthe line 2-2 in Fig. 1.

Fig..3 is a fragmentary vertical sectional View along the line 3 3 in Fig. 1.

Fig. 4 is an outside elevational view of the mold appearing at the left in Fig. 2.

Fig. 5 is a detail cross sectional view takenl along the zone indicatedat 5 5 in Fig. 1.

themselves and then iiows outwardly and i wardly as the molds ll to complete certain parts i of the frame bywhichthe grids are held together until trimmed as above. I thus secure the dis'- tinct advantage over previous molds in that thel metal rst entering the molds pushes out the air from the grid surfaces and warms them so that the balance of the charge necessary to complete the filling will enter all of the'various crev- Fig. 6 is a detail view of aportion of theworlb.

ing face of the stationary mold.

- Referring now more particularly and by reference characters to the drawing I have shownk therein a pair of complementing molds, indicated- `generally at A and B, and for convenience will here refer to them as stationary and movable.

molds, respectively, since they are so arranged in the casting machine of my co-pending application hereinabove identified. 1 It will be understood, however, that as far as material to the present invention it is only necessary that the molds move` together to mate their-casting surfaces, as seenin Fig.2 while the metal is being poured and is cooling, and then that the molds separate far enoughso that the cast plates may drop from between them.

The molds A and B are rectangular blocks ofv` suitable mold metal and having mating working faces I@ which meet closely when the molds close,

matrix surfaces 'are formed.

forming the vertical :and horizontal wires and ribs o r cross bars of the completed grid.v The surfaces .I I I and I 2 form the two battery grids in the single', cast panel or 'plate as aforesaid, and the surthrough` l rounding channels I5 in the matrixes form the frame for the completed grids while the lateral extensions I5 form the lugs by which the grids are subsequently secured to the battery terminals, as will be understood by those skilled in the art.

The molten metal in lling the molds is poured into upwardly flaring mouth surfaces I1 which extend across substantially the full width of the matrix surfaces Il and I2. A series of islands in the working faces form upwardly flaring streamers or grooves I8 which are aligned with the grooves I3 forming the wires, so as to flow the metal directly thereinto. The sizev of thev streamers is greater than that of the wire forming grooves so as to pass the metal rapidly and carry the necessary added volume' for filling' the cross grooves i4 between the wires. Above the streamers I8, and across the full width of the mouth I'I is a channel I9 which forms a pouring gate and attention is called (see Fig. 2) to the point that this gate is thinner than the matrix surfaces I'I and f2. The purpose will presentlyH appear.

There is also cast aroundv the completed" grids a frame which holds them together as they are handled through various operations, and this frame once its purpose is served, is trimmed' on" as scrap. To form this frame the working faces of the molds each has a center channel 20, a lower channel 2| merging at its ends through rounded corner channels 212v with upwardly and outwardly flaring risers or riser channels 2'3- which at upper ends enter lug forming recesses 24. These recesses 24 forml oppositely projecting lugs at upper corners of the cast' plate for handling. The recesses 24 in turn communicate through angular recessesl 25 with upwardly extending exhaust risers or Vent' channels 26 which open through the upper end of" the mold to each side of the filling mouthv I'I. Additionallyv angular bracing rib forming charnlels 2T joinl the' recesses 24y to the side channels i5 and shorter channels 28 join theY recesses 24 with the grid lug recesses I5'. An upper frame channel 29 extends across the top of the' streamers I8 to substantially complete the scrap framing' of the plate.

Attention is called at this point tothe upwardly and outwardly aring or extending channels 3Q which join the channel 29 orupp'er corners o'f the matrix surfaces I`I andi I'2`tothe lower ends of the" vent channels 26, and to the shape of the islands 3i, formed between the recessesv IiiV and 24 and

channels

25, 23 and' 30, which is such that' corners 32 project inwardly almost' to the islands forming the streamers I8 at the extremities of the matrix surfaces.

Connecting the lower ends of the wires I3l and lowerV channel ZI are a series of lower streamers 33.

In operation a charge of molten metal, sufficient to i-lll all the matrix surfaces and scrap frame channels etc., is poured intov the mouth Il and is directed downwardiy by the streamers ig through the matrix' surfaces, and pours through the lower'streainers 33 into thev lower channel 2 l. The aforesaid corners 32 prevent" the metal from flowing outwardl into the lug" forming recesses and connecting channels and asv a result these' are left' free of metal at the outset'. As therr'ietal matrix surfaces and' this air is" directed up- Wardly'and outwardly bythe" metal whiclfirises' in the" risers 23 as the lli'ng continues and the weight of the' following' metal forces the (5 eject the castings from the movable mold I proahead. The air is nally ejected through the exhaust or vent channels 26. The rst metal flowing through the matrix surfaces also warms them, so that they fill readily and completely by the balance of the charge resulting in the formation of a perfect pair of grids. As the metal rises through the lateral corner portions of the mold it finally joins through the channels 3E).

This feed of the metal. is important since it is the latter, hottest part of the metal charge which fills the pre-warmed and evacuated matrix surfaces I I and I2, where the greatest casting perfraction1 is required.

The feed gate I9 is thinner than the balance of the matrix surfaces so that the metal in this gate channel' representing the greatest bulk or mass of metal of the whole plate will cool as rapidly as. the balance of the casting. For a similar reason the channel 2l is also shallow so that the lower scrap frame bar here formed will cool rapidly, and in fact more rapidly than other frame parts. This is of value since' it is upon this-lower edge that the casting drops onto the conveyor, as the molds are separated, and damage to the edge is prevented by'this rapid cooling and hardening. The channels 25 are also shallower than the matrix depth-to retard the metal flow as it rises iinally to the vent channels 26, and it may here be noted that the usual smoke'or mold treatment materiall will be wiped out of the channels 25 so that the metal will rise or' flash only' slightly' into these channels.

For cooling the castings the molds each have a pair of center, vertical bores 34 and outwardly spaced side bores 35 joined at upper ends to the center bores 34 by a transverse bore 35. At lower end the bores 35' communicate with inwardly directed' bores 31 which terminate in downwardly opening bores 33 opening through' the bottom of the mold'. Over thefour open lower ends of the

bores

34 and 38 are secured, foreach mold by cap screws 35, manifolds 40 e'aclihaving a chamber 4I which communicates with the bores 34 and aV chamber 42 which communicates'with the bores 3.8. Tapped opening'sl43 provide means by which Water or other cooling fluid may be piped! into one of the manifold chambers and out through the other to thus circulate through the bores 34. 35, 35., 3'! and 38 as will` be readily understood.

Openings are formed in the panel lugs in the recesses 24, for locating thepanels during'certain operations, by means of plungers 44 (Fig. 3l which project from the working face of the movable mold B int'o contact with boss-like anvil surfaces 45 in the recesses 24 in the stationary mold A. It will benoted that the extremities of the plungers 44 are beveled oilv at 6 while the anvils 45 are similarly but more sharply beveled at 4T. Thus while these parts will form the necessary openings through the lugs, theywill pull free of the metal without-any tendency to cause the lugs to stick to either mold. Each of the plungers 44 is slide-ble through an opening 48 in the mold B and is braced against anexpansionl coil spring 49 which urges the plunger toward mold A. rlhis movement is limited andv accurately adjusted by a stopnut 5D, and lock nut 5I, which contact the mold and are so adjusted that. as the molds come together, the plunger bears with spring induced pressure on the anvil 45. A Cap 52 is held-by a stud 53 over these nuts.

As the molds separate following each filling the cooled casting is carried by the UICN/able mold B out of the stationary mold and to then positively scope of the appended claims.

vide knock-out pins 54 at strategically spaced locations about the matrix surfaces H and I2 of the movable mold. These knock-out pins are slidably mounted through openings 55 in the mold and into cages 55 secured thereto, springs 5i being arranged to normally hold the pins iiush at their ends with the matrix surfaces (Fig. 2). As the mold B moves away from the stationary mold the pins 54 are arranged to strike stops (not shown) which thrust them out into the matrix surfaces and so push the castings clear.

Attention is called to the formation of the lug forming recesses 2li in the stationary mold A. As shown the depth of the outer extremities of these recesses indicated at 24a, is less than that oi the balance of the recesses so that the outer p0rtions of the lugs themselves will be reduced in thickness. Actually, these outer portions 2ia of the recesses will remain the same in all molds regardless of the thickness of the plates cast by the molds, so that the outer ends of all plate lugs will be of the same thickness, and, of course, in the case of the thinnest plates cast there may be no offset or reduction in the lug recess depth as will be understood.

It will be thus seen that the plates regardless of thickness may pass at the lug ends through a stripping or feeding Zone of constant size, as pointed out in my prior co-pending application for Automatic plate trimming machine, Serial Number 703,799, filed October 17th, 1946.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. A battery grid plate casting mold having an intaglio matrix surface forming a substantially rectangular casting cavity shaped to form the grid plates and a filling gate extending across substantially the full width of the cavity, the said cavity also including riser channels extending upwardly from the lower corners of the cavity and opening through the top of the mold so that air driven ahead of metal pouring through the gate and down through the cavity may escape, the mold also having lateral recesses extending outward from the channels to form handling lugs on the completed casting, and the outer portions of said recesses being of lesser depth than the inner portions to correspondingly reduce the thickness of the outer ends of said lugs.

2. A battery grid plate casting mold having an intaglio matrix surface forming a substantially rectangular casting cavity shaped to form the grid plates and a filling gate extending across substantially the -full width of the cavity, the said cavity also including riser channels extending upwardly in diverging relation from the lower corners of the cavity and opening through the upper part of the mold whereby the metal poured down into the cavity may drive the air ahead as it iills the cavity and finally rises in said channels, and the mold having other channels connecting the upper corners of the cavity to the riser channels and edge portions formed by said channels and projecting toward the path of metal flowing down through said lling gate to divert the metal into the cavity until it is completely filled.

3. A battery grid plate casting mold having an intaglio matrix surface forming a substantially rectangular casting cavity shaped to form the grid plates and a filling gate extending across substantially the full width of the cavity, the said cavity also including riser channels extending upwardly in diverging relation from the lower corners of the cavity and opening through the upper part of the mold whereby the metal poured down into the cavity may drive the air ahead as it iills the cavity and finally rises in said channels, and the mold having also three angularly related channels connecting the sides and upper corners of the cavity to the riser channels.

4. A battery grid plate casting mold having an intaglio matrix surface forming a substantially rectangular casting cavity shaped to form the grid plates and a iilling gate extending across substantially the full width of the cavity, the said cavity also including riser channels extending upwardly from the lower corners of the cavity along the sides of the cavity and opening through the upper part of the mold whereby the metal poured down into the cavity through the filling gate may drive the air ahead as the metal iills the cavity and iinally rises into said channels, and the riser channels having portions of reduced depth as compared to their overall depth to retard the upward ow of the metal and ensure the complete filling of the casting cavity.

5. A battery grid plate casting mold having an intaglio matrix surface forming a substantially rectangular casting cavity shaped to form the grid plates and a, lling gate extending across substantially the full width of the cavity, the said cavity also including riser channels extending upwardly from the lower corners of the cavity along the sides of the cavity and opening through the upper part of the mold whereby the metal poured down into the cavity through the filling gate may drive the air ahead as the metal fills the cavity and finally rises into said channels, and the riser channels having portions of reduced depth as compared to their overall depth to retard the upward iiow of the metal and ensure the complete lling of the casting cavity, the said retarding portions of the channels being located above the level of and communicating with the upper corners of the casting cavity.

6. A battery grid plate casting mold having an intaglio matrix surface forming a substantially rectangular casting cavity shaped to form the grid plates and afilling gate extending across substantially the full width of the cavity, the said cavity also including riser channels extending upwardly from the lower part of the cavity and a cross channel across the bottom of the cavity connecting the cavity and riser channels, and the filling gate and cross channel being both of lesser depth than the cavity whereby to accelerate the cooling of the metal in the gate and this channel.

ARTHUR D. LUND.

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

a UNITED STATES PATENTS Number