US2704388A - Die casting apparatus - Google Patents

Description

March 22, 1955 v, w sT ET AL DIE CASTING APPARATUS Filed May 20, 1949 3 Sheets-Sheet l INVENTORS V J. WEST F. C. STOCKHAM ATTORNEY March 22, 1955 v WEST ET AL 2,704,388

DIE CASTING APPARATUS Filed May 20, 1949 3 Sheets-Sheet 2 INVENTORS V J. WEST BY E C. STOCKHAM ATTORNEY March 22, 1955 v, w s ET AL 2,704,388

DIE CASTING APPARATUS Filed May 20, 1949 3 Sheets-Sheet 5 ATTORNEY United States Patent DEE CASTING APPARATUS Vivian 3. West and Frederick C. Stockham, Wolverhampton, England, assignors to The Wolverhampton lDie-Casting Company, Limited, Wolverhampton, Engand Application May 20, 1949, Serial No. 94,482

3 Claims. (Cl. 22-57) This invention relates to the moulding of articles, and has for its object to provide an improved pressure moulding process and means for use therewith. The invention is applicable to the moulding of metal articles by the die-casting process and also to the moulding of articles from other mouldable materials which, when introduced into the dies, may be in powdered, solid or semi-solid form.

Heretofore, in the process of die-casting, it has been usual to provide a passage, known as a sprue passage, in one of the dies and leading to the mould which is formed between the dies in which the article is cast. When the article has been cast, the stump of metal, formed by the sprue passage and known as the sprue, has to be removed from the cast article, whilst the flash which is formed around the article where the dies meet also requires to be removed. The sprue and flash have been removed by one or more separate operations.

In the moulding of articles from mouldable materials which are introduced into the mould in powdered, solid or semi-liquid form, there is usually no sprue although there is generally a flash which has to be removed.

In the process according to the present invention the article and the sprue, if any, is moulded integrally with a web to form a slug, and the slug is utilised to convey the article from the casting position to at least one other position for a further operation. This further operation may be the parting of the article from the slug, or there may be a number of operations upon the article in the slug before the article finally is parted therefrom.

As applied to the die-casting of metal articles, the article and the sprue would be cast integrally with and be spaced apart by a portion of the web so that when the article has been parted from the slug the remainder thereof, including the web and sprue, can be returned to the melting pot.

in carrying out the invention a space is left between the die faces when closed, whereby when the article is moulded it is formed integrally with a web to form a slug for conveying the article to another position for at least another operation, preferably in the same machine. As applied to die-casting where there is a sprue passage from the melting pot, the sprue passage would lead into the space between the die faces at a location removed from the mould so that the molten metal will flow through the inter-die space to the mould and so produce a slug in which the article and sprue are moulded integrally with and spaced apart upon a web.

The slug may be moulded or cast between guides in which it is moved endwise, the arrangement preferably being such that each slug, as it is moulded or cast, becomes conneeted or fixed to the trailing end of the previously formed slug so that there is produced a continuous succession or ribbon-like strip of connected slugs from which the articles are parted in turn In order that the invention may be clearly understood it will now be more fully described with reference to the embodiments, shown by way of examples, in the accompanying drawings; in which:

1 is a side elevation of a die-casting machine with the dies closed.

Fig. 2 is a similar view to Fig. 1 but showing the dies partially opened to clear the sprue.

Fig. 3 is a sectional side elevation of the same machine but showing the dies opened fully to clear the cast article.

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Fig. 4 is a sectional side elevation of the same machine, the section being taken through the tools for parting the cast article from the slug.

Fig. 5 is a perspective view of the carrier in which the slugs are cast and moved endwise in a ribbon-like strip.

Fig. 5A is a longitudinal sectional view of the carrier and dies as shown in Fig. 2 with portions broken away.

Fig. 5B is a longitudinal sectional view of the carrier and dies as shown in Fig. 1 with portions broken away.

Figs. 6 and 7 are rear and front elevations respectively of one of the slugs cast in the machine.

Referring to the drawings and more particularly to Figs. 1 to 5, a die 1 is mounted in a fixed plate 2, known as the furnace plate, and the other die 3 is mounted in the opposing face of a movable plate 4 known as the ejector plate. Between the plates 2 and 4 is a carrier comprising horizontal bars 5 interconnected in vertically spaced relationship by end members 6, the opposing faces of the two bars 5 being formed with central longitudinal channels 7 which constitute guides. The dies 1, 3 are so set that when they are in the closed or casting position, as shown in Fig. 1, there is a narrow space between their confronting faces, which space extends substantially over the whole area of said faces and is coextensive with the guide channels 7 in the top and bottom bars 5 of the carrier.

A sprue passage 8, through the furnace plate 2, instead of communicating directly with the mould formed by the dies 1, 3, leads from the injection nozzle 9 of the machine to the narrow space between the confronting die faces at a location laterally displaced from the mould. This narrow space is closed at one end by a vertical and rearwardly projecting end flange 10 on the stationary die 1, and at its other end it is closed by the trailing end of the previously cast slug which has been pushed endwise from the casting position and is still within the guides afforded by the channels 7 in the carrier bars 5. As a consequence the charge of molten metal injected through the sprue passage "8 flows through the narrow space to the mould and to said channels so as to produce a rectangular slug (see Figs. 6 and 7) consisting of top and bottom parallel bars 11 connected by a thin web 12 in which is carriedthe cast article 13 and a laterally displaced sprue 14.

In this embodiment the article 13 is a knob having an axial recess in its shank portion, said recess being formed by the forward end of a spindle 15 which is carried by an auxiliary ejector plate 16 and projects through a hole in the ejector plate 4 into the mould of the die 3.

The furnace plate 2 is connected by parallel guide rods 17 to a fixed crosshead 18 and upon these rods 17 the ejector plate 4, auxiliary ejector plate 16 and a hollow slide block 19 are adapted to slide axially, the slide block being rigidly connected by screws 20 to the rear face of the auxiliary ejector plate 16. The bars 5 of the carrier are mounted to slide on pins 21 projecting forwardly from the ejector plate 4 through hearing holes in said bars 5, which pins 21 enter registering guide holes 22 in the furnace plate 2 when the dies 1, 3 are closed. Pins 23 screwed into the auxiliary ejector plate 16 and passing through holes in the ejector plate 4 have headed forward ends which work in counter-bores and limit the extent to which these two plates can be separated, whilst distance pins 24 screwed into the rear face of the ejector plate 4 extend rearwardly through clearance holes in the auxiliary ejector plate 1.6 and carry discs 25 to the rearmost of which are fixed stop pins 26, adapted to co-operate with the rear wall of the hollow slide block 19, and a stout central spindle 27 which passes through a hole in said rear wall and has a tapered rear end.

A transverse shaft 28 mounted for rotation in the fixed crosshead 18 and adapted to be turned by a lever 29 has levers 30 fixed one at each end and these are connected by links 31 to points of pivotal attachment on the opposite sides of the slide block 19, the levers 3 30 and links 31 operating as toggles. Housed in a recess in the fixed crosshead 18 and fixed on the shaft 28 is a stepped stop member 32 which is adapted to cooperate with the rear end of the spindle 27.

Pivoted to opposite ends of the carrier are rearwardly extending catch levers 33, one at each end, and the toothed portions 34 engage behind abutments 35 on the sides of the slide block 19 to retain the auxiliary ejector plate 16, ejector plate 4 and carrier bars 5 together as shown in Fig. l. Laterally projecting studs 36, for tripping the catch levers 33 as the toggles are broken, are provided at appropriate positions on the links 31.

After each slug is cast the lever 29 is operated to break the toggles and draw back the carrier, and with it the ejector plate 4, auxiliary ejector plate 16 and slide block 19, away from the furnace plate 2; this draws back the slug away from the die 1 and the sprue 14 from and clear of the sprue passage 8. Continued movement of the lever 29 and breaking of the toggles first causes the studs 36 to trip the catch levers 33 so as to free them from the abutrnents 35 as shown in Fig. 2, and then draws the slide block 19 and auxiliary ejector 16 away from the rear of the ejector plate 4 to the extent permitted by the pins 23 so as to draw back the spindle 15 in the die 3. During the separation of the auxiliary ejector plate 16 from the ejector plate 4 the latter is held up by the spindle 27 engaging the nose of the stop member 32 until finally the latter is moved out of the way. Still further continued movement of the lever 29 draws back the slide block 19, auxiliary ejector plate 16 and ejector plate 4 together away from the carrier bars 5 until finally the tapered rear end of the spindle 27 engages the base of the step in the stop member 32. The parts are then in the positions shown in Fig. 3, the die 3 having been withdrawn clear of the article 13 in the slug.

The cast slug is now moved endwise or advanced by fingers 37 which slide in the guide channels 7 at one end and are carried by a slide block 38 mounted between the bars 5 and operated by the rod 39 of a piston 40 which works in a fluid pressure cylinder 41 (see Fig. 5). The stroke of the piston is slightly less than the lateral dimension of the die faces so that when the dies are closed again, by reverse operation of the lever 29, the trailing edge of the previously cast slug will close that end of the inter-die space remote from the flange 10. Before the dies close again, however, the slide block 38, with its fingers 37, is returned to its original position. The leading ends of the fingers 37 have small spigots 42 (see Fig. 6) which form sockets 43 (see Fig. 7)

in the adjacent ends of the slug bars 11. It will be apparent that the slugs are fed a fixed amount at each feeding stroke and the severing means is spaced from the corresponding dies a distance which is equal to a multiple of the feeding stroke whereby the article may be separated from the slug simultaneously with the molding of a subsequent article by a severing means mounted on the die supporting plates.

When the dies are again closed and the next slug is cast it connects on to the trailing end of the preceding slug, and so on to form a ribbon-like strip of slugs, as shown in Fig. 5, which after each casting operation is moved endwise one step along the guide channels 7 in the carrier bars 5.

Each time the dies 1, 3 close, the cast knob 13 is parted from the slug by the co-operation of a punching die 44 and anvil die 45 respectively which are mounted in the ejector plate 4 and furnace plate 2 at a laterally spaced position corresponding to that of the article or knob 13 in one of the previously cast slugs in the strip. In Fig. 5 the left-hand or first slug in the strip has just been cast and, at the same time, a knob has been parted from the third slug from the left, so

that the ribbon-like strip, minus the articles. but with the sprues 14 still attached issues step by step from the right-hand end of the carrier ready to be returned to the melting pot. The punching die 44 and anvil die 45 are shown in Fig. 4. The articles 13 parted from the ribbon-like strip in succession are forced through the central passage of the anvil die 45 and fall through a passage 46 in the furnace plate 2 to a convenient receiver beneath it.

When casting the first slug of a series, the outlet end of the inter-die space would require to be closed by a blanking plate. Thereafter the previously cast slug will serve to close that end of said space and casting can proceed as above described, the successive slugs becoming connected together into a ribbon or strip.

Having fully described our invention, what we claim and desire to secure by Letters Patent is:

l. A die casting apparatus comprising a pair of die supporting plates arranged in face to face relation mounted for relative movement toward and away from each other along a longitudinal direction, a pair of guide channel bars positioned in parallel spaced apart relation between said plates and being mounted for movement relative to said plates so that said channel bars may be spaced from both of said plates when the plates are separated, said guide channel bars being provided with grooves on their adjacent inner facing edges, article forming dies mounted on said plates and projectable into the space between said channel bars, said plates being so arranged that in their closest position a space is maintained therebetween for passage of the moldable material from the mold cavity formed by said dies and into the space formed by the grooves in said channel bars, means supported by and mounted for movement relative to said channel bars for engaging the portions of a slug formed in said channel grooves and feeding said slug including said article a fixed distance whereby said article entirely clears said dies, said feeding means including slug engaging fingers in the grooves of said channel members and a source of power for moving said fingers said fixed distance.

2. A die casting apparatus comprising a pair of dies with an article forming cavity therein when closed and arranged in face to face relation and mounted for relative movement toward and away from each other, a pair of guide channels positioned in parallel spaced apart relation in a plane between and transverse to the direction of movement of said dies and mounted for movement relative to said dies so that said guide channels may be spaced from both of said dies when the dies are separated, the channel of each guide channel being on the inner face thereof and facing the channel of the other guide channel, said dies including portions cooperating with said channels, and communicating therewith for forming a slug with the article, said dies being so arranged that in their closest position a space is maintained therebetween over a substantial portion thereof for the passage of the mouldable material into the mould cavity formed by said dies and into the space formed by said channels, advancing means including slug engaging fingers in the channels of said guide channels, and means for moving said fingers and thereby advancing the slug away from said die cavity.

3. A die casting apparatus comprising a pair of dies with an article forming cavity therein when closed and arranged in face to face relation and mounted for relative movement toward and away from each other, a pair of guide channels positioned in parallel spaced apart relation in a plane between and transverse to the direction of movement of said dies and mounted for movement relative to said dies so that said guide channels may be spaced from both of said dies when the dies are separated, the channel of each guide channel adapted to be disposed for communication with the die cavity when the dies are closed, said dies including portions cooperating with said channels, and communicating therewith for forming a slug with the article, said dies being so arranged that in their closest position a space is maintained therebetween over a substantial portion thereof for the passage of the mouldable material into the mould cavity formed by said dies and into the space formed by said channels. advancing means including slug engaging fingers in the channels of said guide channels. and means for moving said fingers and thereby advancing the slug away from said die cavity.

References Cited in the file of this patent UNITED STATES PATENTS (Other references on following page) UNITED STATES PATENTS Stern Feb. 7, 1939 Tegarty Oct. 31, 1939 Brown May 14, 1940 5 Sundback Aug. 26, 1941 Morin et a1 Dec. 16, 1941 Morin Jan. 16, 1945 Morin July 27, 1948 Wilhelm Sept. 25, 1951 10 6 FOREIGN PATENTS France Jan. 22, 1945 OTHER REFERENCES

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