US2804662A

US2804662A - Simultaneous casting and trimming apparatus

Info

Publication number: US2804662A
Application number: US525203A
Authority: US
Inventors: Howard W Bartholomew
Original assignee: Nat Lead Co
Current assignee: NL Industries Inc
Priority date: 1955-07-29
Filing date: 1955-07-29
Publication date: 1957-09-03
Anticipated expiration: 1974-09-03

Description

Fig. I.

Sept. 3,1957 H.'W. BARTHOILQMEW 2,804,662

SIMULTANEOUS CASTING AND TRIMMING APPARATUS Filed July 29, 1955 6 Shee'ts-Sheet 1 I s INVENTOR.

m x V 7 Howard \MBar tholomew I I BY G QJ' 11 TTORNE I I Sept. 3, 1957 H. w. BARTHOLOMEW- SIMULTANEOUS CASTING AND TRIMMING APPARATUS 6 Sheets-Sheet 2 Filed July 29, 1955 Fig. 2.

I NVE N TOR.

BY i i ATTORNEY H. w. BARTHOLOMEW 2,804,662

SIMULTANEOUS CASTING AND TRIMMING APPARATUS 6 Sheets-Sheet 3 W e m w 5 m N h E n 9 M m I L I li| Ill ||m iilfifil wmw m mvl l w m m m JTTORNEY Selp t. 3, 1957 Filed July 29, 1955 Sept. 3, 1957 H. w. BARTHOLOMEW 2,804,662

SIMULTANEOUS CAS'f'ING AND TRIMMING APPARATUS I Filed July 29, 1955 e Sheets-Sheet 4 Fig. 6.

1 NVE N TOR.

34 Howard W. Boriholomew Sept. 3, 1957 w. BARTHOLOMEW SIMULTANEOUS CASTING AND TRIMMING APPARATUS 6 Sheets-Sheet 5 Filed July 29, 1955 INVENTOR.

Howard W. Bartholomew Fi IQ.

IITTORNEY Sept. 3, 1957 H. w. BARTHOLOMEW 2,804,662 SIMULTANEO US CASTING AND TRIMMING APPARATUS Filed- Ju1y'29, 1955 6 Sheets-Sheet 6 Q EE VN 9:1 2.5m

EE v ua 3.5m

SIMULTANEOUS CASTING AND TRIMMING APPARATUS Howard W. Bartholomew, Pottstown, Pa., assignor to National Lead Company, New York, N. Y., a corporation of New York Application July 29, 1955, Serial No. 525,203

Claims. (Cl. 22-57) This invention relates to means for pressure die casting. More specifically it relates to apparatus for simultaneously carrying out casting and trimming operations.

In the production of cast pieces by pressure die casting methods, it is customary to force a charge of molten metal under pressure into a suitable die. The molten metal in the die is allowed to cool and thus solidify into a solid casting. The casting, however, normally has attached to it some extraneous solidified metal known as gate" and/ or flashing which must be removed in order to finally obtain a finished casting having the desired configuration. The gate and/ or flashing is in part sometimes deliberately formed in order to support the casting and provide area for contacting ejecting pins and the like and is also in part an inherent result of the pressure die casting technique. When employing pressure die casting methods to produce large numbers of identical pieces and in particular when very small castings are produced, it becomes extremely important from the economical view point to produce the finished trimmed cast piece with a minimum amount of handing.

Accordingly, an object of the instant invention is to provide means for simultaneously casting and trimming pieces of some desired configuration. Another object is to provide apparatus which permits pressure die casting of a piece and simultaneous trimming of an identical piece which has just been cast. Another object is the provision of apparatus unitarily arranged for carrying out casting and trimming operations in an integrated and eflicient manner. Still another object is to provide an improved apparatus for casting a plurality of small pieces and for trimming the flashing therefrom. These and other objects of the instant invention will become evident from the following more complete description and from the drawings.

Broadly, the simultaneous casting and trimming operation as herein contemplated is made possible by the construction of apparatus incorporating a movable carrier bar which supports the casting as formed and transfers it to a trimming station positioned adjacently to the casting die. This principle is more clearly demonstrated by considering the drawings wherein briefly:

Fig. 1 represents a vertical side view of apparatus according to the instant invention, and

Fig. 2 taken along line 2-2 of Fig. 1 shows in front elevation a typical cover die as hereinafter more fully described.

Fig. 3 taken along line 33 of Fig. 1 illustrates the details of the passage provided for introduction of molten metal into the assembled die.

Fig. 4 taken along line 44 of Fig. 1 shows in front elevation a typical ejector die and the carrier bar which when assembled in contact with the cover die shown in Fig. 2 form a completed die.

Fig. 5 taken along line 5-5 of Fig. 4 shows a horizontal construction of suitable gate ejecting pins asis know to the art.

nited. States Patent Figs. 6-8, all in side elevation, show in sequence the relative positions of the cover die, the ejector die, and the carrier bar during stages of the casting and trimming operation.

Fig. 9 shows the carrier bar in cross section partially cut away.

Fig. 10 shows a typical assembly of small cast pieces as may be initially produced with the flashing still surrounding each piece and Fig. 11 shows in front elevation a trimmed casting from Fig. 10.

Fig. 12 shows schematically a top view of typical apparatus employing the instant principle including a casting station and two adjacently positioned trimming stations.

Figs. 13-21 are schematic top views of the apparatus as identified in Fig. 12 and show sequentially the relative position of the parts as an operational cycle is conducted.

Considering now the drawings in some greater detail in Fig. 1 there is shown carrier bar 10, cover die 12, and ejector die 14 which parts are operably positioned generally between front plate 16 and movable back plate 18. Cover die 12 as more clearly shown in Fig. 2 is a stationary part and is provided with a plurality of recessed cavities 20 into which die sections can be inserted and retained. Of course this construction is not limited to the particular die section as illustrated. Other modifications including provisions for casting more or fewer pieces as well as larger or smaller pieces is also contemplated as being within the scope of this invention. The cover die is provided with passageway 22 which opens into sprue plug 24 of carrier bar 10 and thus permits a shot of molten metal to be introduced by suitable means, not shown, into the assembled die.

The construction of carrier bar 10 and its relationship to the ejector die 14 can be better appreciated by considering Fig. 4, Fig. 5, and Fig. 9. The carrier bar 10 is of generally rectangular shape and is horizontally movable in two directions. It is capable of movement to and away from the cover die and can also index or move in a direction normal to such movement. According to the instant construction the carrier bar is provided with two sprue plugs 24 which have a number of functions. The sprue plug permits introduction of the molten metal through gate runners 26 and into the die interior. The sprue opening is also filled with metal in the casting operation as is shown in Fig. 10 and the sprue plug then acts as a support for the casting. The casting so supported by the sprue plug 24 of the carrier bar 10 may then be moved to a trimming station 36. The two sprue plugs 24 are so positioned relative to one another that while the one supports a casting at the trimming station 36 the other will be aligned with the passageway 22 of cover die 12 and thus permit casting of another piece. As indicated carrier bar 10 is provided with gate ejecting means such as sprue ejectors 28. These pins which may be constructed as is known to the art are positioned in the vicinity of sprue plugs 24 and'are employed to eject the gate 30 from the sprue plug thereby permitting the gate and flashing to be discarded from the apparatus after the cast pieces have been trimmed.

As shown in Fig. 4 carrier bar 10 and ejector die 14 contact one another along parting line AA and when so positioned form one side of the die assembly, the surfaces of which are arranged for close and matching contact with cover die 12. By appropriate movement either sprue plug 24- of carrier bar 10 can be positioned for contacting the ejector die as shown.

As is shown schematically in Figs. l22l two trimming stations 36 are positioned equidistant on either side of the casting station. The particular trimming means which may be employed is not limited vand those which are known in the art are generally suitable. For example a trimming die 38 comprising a stationary block having holes identical in shape to the periphery of the casting may be employed. Suitable trimming punches 40 may be employed in cooperation with the trimming die 38 whereby the finished casting may be punched out :from the surrounding flashing. It has been found desirable to employ a stripper plate 42 to assist in supporting the gate assembly while trimming and for aiding in the stripping of the gate or flashing from the carrier bar as mentioned previously.

A typical operational cycle will now be described. Reference is made to Figs. 6-8 for the relative movement of the carrier bar 10, cover die 12, and ejector die 14. Also Figs. 12-21 will show the sequential movement and positioning of the castings in relation to the casting and trimming stations. Consider now that the cover die 12, and carrier bar 10, and ejector die 14 are all in fully closed position as shown in Fig. 13. Molten metal such as for example zinc or aluminum or alloys thereof is forced under pressure into the die cavity. After a predetermined period sufiicient to permit solidification of the molten metal the opening cycle starts.

The ejector die 14, ejector pins 32, carrier bar which supports the gated casting, all being in intimate contact begin to move away from the cover die 12 for a predetermined distance say /2 inch. (See Fig. 6 and Fig. 14.)

The carrier bar it) then stops. The ejector pins 32 also stop. The gated casting which is held in the carrier bar and is additionally supported by the ejector pins also stops. The ejector die 14, however, does not stop but continues back for an additional distance, for example inch more. See Fig. 7 and Fig. 15. The rearward movement of carrier bar 10 is controlled by appropriate means such as for example carrier bar stop 34.

The ejector die continues to move back for a still additional distance of say 4 inch (thus having moved typically for a total opening of one inch), and in so doing carries the ejector pins away from the gate. (See Fig. 8.) This movement leaves the gated casting supported only by the carrier bar. In a typical operation the ejector pin mechanism is spring loaded during the final movement inch) of the ejector die 14.

The carrier bar then indexes or moves to the trimming station in a direction normal to its opening motion. (See Fig. 16.) This movement is accomplished by conventionalmeans as will be appreciated by those skilled in the art. After moving the gated casting as indicated, the carrier bar 10 now moves into the trimming position. This movement according to the example used herein will be for a distance of /2 inch toward the cover die 12 or trimming die J8 a shown in Fig. 17. The casting is now in intimate contact with the trim die plate 38 and the second sprue plug 24 of carrier bar 10 is in contact with the cover die 12 and coincides with passageway 22. Simultaneously with such movement of the carrier bar it), the ejector die 14 is moving into closed position (for example for a distance of one inch). The ejector pins 32 automatically are placed in proper position during thi movement by virtue of the spring loading previously mentioned.

As indicated in Fig. l the ejector die is attached to movable support back 18. Trimming punches 40 are arranged in fixed position to the movable back plate 18 and move with the back plate and relative to the ejector die 14. When the ejector die 14 is against the cover die 12 the trimming punches 40 are against the castings but have not yet punched them from the gate and flashing.

The stripper plate 42 is also spring loaded and is arranged to move relative to the ejector die 14 and to the trimming punches 40 and moves against the gated casting so as to support same. (See Fig. 17.)

The apparatus is now assembled for formation of another casting and for trimming of the pieces which have just been cast. Simultaneously with the introduction of .4 another shot of molten metal into the die cavity, the trimming punches 40 are activated and are pushed forward (for example about 7 inch). This action punches out the finished casting as shown in Fig. 18.

Gate ejecting means such as sprue ejectors 28 are located on either side of the sprue plug in the carrier bar and are arranged to force-the gate from the carrier bar. This action is in effect simultaneous with the trimming. As the carrier bar it) once again begins to open away from the cover die 12 and trimming die 38 the gate falls free from the apparatus assisted by the action of the stripper plate 42 on its opening cycle.

The cycle just described is then again repeated as shown in Figs. 18-21. However, as will be appreciated the carrier bar is now indexed so as to move the cast piece to the trimming station opposite that employed as just mentioned.

it is evident from the preceding description and from the drawings that the instant die casting apparatus wherein the unique carrier bar is incorporated represents a definite advance to the die casting art. Although the principle of operation is not restricted to any size casting, it is obvious that apparatus of the instant type can greatly increase the yield of small castings for any given time period.

While this invention has been described above and shown in the drawings, it is not meant to be limited thereto and is intended to include all those devices coming within the scope of the following claims.

I claim:

1. Simultaneous casting and trimming apparatus comprising a pressure casting station and two trimming stations which are horizontally positioned on opposite sides of said casting station, said casting station including a stationary cover die, a movable ejector die, and a carrier bar of generally rectangular shape and being movable to and away from the cover die and also being movable in a direction normal thereto, said carrier bar having a pair of identical sprue openings for supporting a pressure die casting and for transporting same to one of the trimming stations.

2. Simultaneous casting and trimming apparatus comprising a pressure casting station and two identical trimming stations which are horizontally positioned equidistant on opposite sides of said casting station, said casting station including a stationary cover die, a movable ejector die, and a carrier. bar of generally rectangular shape and being movable to and away from said cover die and also being movable in a direction normal thereto, said carrier bar having a pair of identical sprue openings for supporting a pressure die casting and for transporting same to one of the trimming stations.

3. Simultaneous casting and trimming apparatus comprising a pressure casting station and two identical trimming stations which are horizontally positioned equidistant on opposite sides of said casting station, said casting station including a stationary cover die, a movable ejector die, and a carrier bar of generally rectangular shape, said carrier bar being movable to and away from said cover die and also being movable in a direction normal thereto, said carrier bar being of such length so as to extend from the casting station to either of the trimming stations, said carrier bar having a pair of identical sprue openings for supporting pressure die castings, said sprue openings being positioned so that one is at the casting position when the other is at the trimming position.

4. Simultaneous casting and trimming apparatus comprising a pressure casting station and two identical trimming stations which are horizontally positioned equidistant on opposite sides of said casting station, said casting station including a stationary cover die having a passageway for introduction of molten metal into the die cavity, a movable ejector die, and a movable carrier bar so arranged in contact with said ejector-die as to form one side of the die assembly when in closed position, said carrier bar having a pair of identical sprue openings for supporting pressure die castings, said carrier bar designed for horizontal movement between the casting station and the trimming stations in such manner as to permit simultaneous casting and trimming operations.

5. Simultaneous casting and trimming apparatus comprising a pressure casting station and two identical trimming stations which are horizontally positioned equidistant on opposite sides of said casting station, said casting station including a stationary cover die having a passageway for introduction of molten metal into the die cavity, a movable ejector die, and a movable carrier bar so arranged in contact with said ejector die as to form one side of the die assembly when in closed position, said carrier bar having a pair of identical sprue openings capable of supporting pressure die castings, said ejector die and carrier bar being movable to and away from said cover die, said carrier bar further being movable in a direction normal to said cover die and between said casting station and said trimming stations, the sprue openings of said carrier bar being positioned relative to one another so that one is at the casting position when the other is at the trimming position, means for trimming the casting, and coordinated means for forming another casting simultaneously with said trimming.

References Cited in the file of this patent UNITED STATES PATENTS 457,879 Madden Aug. 18, 1891 1,570,658 Wickland et a1. Jan. 26, 1926 1,815,361 Morris et al July 21, 1931 2,058,762 Bible Oct. 27, 1936 2,076,374 King Apr. 6, 1937 2,367,303 Morin Jan. 16, 1945 2,494,777 Patterson et a1 Jan. 17, 1950 2,569,083 Wilhelm Sept. 25, 1951 2,704,388 West at al Mar. 22, 1955 FOREIGN PATENTS 641,858 Great Britain Aug. 23, 1950