US2995788A - Method and mechanism for casting and sprue removal - Google Patents

Description

Aug. 15,1961 K. SUNDAY 2-,995788 Filed May 2s, 195a METHOD AND MECHANISM FOR CASTING AND SPRUE REMOVAL 3 sheets-sheet .1

7 INVENTOR.

' g- 15, 1961 RVK. SUNDAY I 8 METHOD AND MECHANISM FOR CASTING AND SPRUE REMOVAL I Filed May 28, 1958 s Sheets-Sheet 2 F l 5! 5. INVENTOR.

Aug. 15; 1961 VR.K.SUINDAYI 2,995,7 9

METHOD AND MECHANISM FOR CASTING AND SPRUE REMOVAL Filed May 28. 1958. s'sneezs sneet s 'i INVENTOR. Mam/P0 s n/my BY wg/M 2,995,788 METHOD AND MECHANISM FOR CASTING AND SPRUE REMOVAL Richard K; Sunday, Kokomo, Ind., assignor to Perfect Equipment Corp., Kokomo, Ind., a"corporation of a Filed May 28, 1958, Ser. No. 738,527

12 Claims. (Cl. 22-116) My invention relates to a new and improved mech anisrn and method for die casting and is particularly directed to a novel means for severing the sprue.

I sprues to thereby permit the casting to fall freely from the die cavity.

Another object is the provision of a die assembly whereby the casting will be automatically ejected from the die cavity without ejector pins or a complicated ejector structure.

Other objects will become apparent from time to time throughout the course of the following specification and claims.

I illustrate my invention more orless diagrammatically in the accompanying drawings wherein:

FIGURE 1 is a perspective view of my machine showing the dies in an assembled position preparatory to receiving a charge of metal;

FIGURE 2 is a plan view. of the die assembly with the front and rear die blocks separated .to expose the rear dies;

FIGURE 3 is a sideelevation with parts broken away of the assembly of FIGURE 2; 9 FIGURE 4 is an elevation of the front die and one of the two rear dies;

FIGURE 5 is a cross section taken substantially along line 5-5 of FIGURE 4;

FIGURE 6 is a partial section, on an enlarged scale, taken substantially along line 66 of FIGURE 5, and

FIGURE 7 is a front elevation of one ofthe rear dies.

Like reference numerals will beused to'indicate like parts throughout the description of the following draw.- mgs.

Referring now to FIGURE 1, my machine is shown in perspective as consisting essentially of a melting and holding pot 2 which may contain conventional heating elements to either heat and maintain or merely maintain a predetermined temperature in the pot, and a die assembly. On the forward edge of the pot is a support plate 4 on which my new and improved die assembly 6 is mounted by means of brackets 8 and suitable connecting means 10. Secured to the rear of the die assembly 6 is a conventional pump 12 for injecting lead or other low melting point alloy 14 from the pot through an injection nozzle 16 as best shown in FIGURE 2 into the die assembly. A funnel or chute 17 extending from beneath the die assembly directs the casting ejected from the dies into a discharge and collection bin 18. A side standard 20 may hold a fuse box, safety switches and other miscellaneous equipment. The machine may be operated by an operator who sits in front of the discharge bin. 9

The die assembly 6 consists essentially of a pair of side plates 22 having projecting legs 24 (see FIGURE 3) United States Fatent O 2 adapted for engagement with the brackets 8, a front cross bar 25 and a rear cross bar 26. A pair of'slideways 28 are mounted on the side plates 22 to permit reciprocation of the front die block as 'will be hereinafter described.

A manual lever 30 is pivoted at 32 on front cross bar 25 to reciprocate the front die block between a closed easting position and an open ejecting position.

Referring now to FIGURES 2 and 3, my die assembly I is shown as comprising a front die block 40 and a rear die block 42, the latter being secured to the rear cross support bar 26. Front die block 40 is fastened to a pair of cams 44 and 46 by suitable bolts 48 and'50 and reciprocates along slideways 28.

Cams 44 and 46 have'camways 72 and 74 respectively which receive cam rollers 81 and'82 carried by the rearat 32. By movement of handle to the right from the position shown in FIGURE 2, the front die block with its connected earns 44 and 46 will move toward the stationary rear die block.

The front die block is recessed'as at 58 to receive front die 80 and has a recess 60. having its forward edge 62 disposed in substantially parallel alignment with the I rearward edge 64 of recess 58. A suitable connecting means, such as bolt 66, may securely fasten front die '80 to the front die block. i I In FIGURE 2 a pair of lower guide members 83, 84

- and an upper guide member 85 are shown fastened to rear die block 42 to form slideways for the rear dies 86 and "87. The upper guide member may partially cover the end of nozzle 16 or be recessed to permit more ready access to it. i

Referring now to FIGURES 4 through 7 of the drawings, and particularly FIGURE 7 initially, the dies themselves are illustrated. In FIGURE 7, left rear die 86 is shown as consisting of a main body portion 90 and an end extension 92 having a hole 94 for the reception of cam roller 81. Upper and lower cross slide channels 95 and 96 are adapted to slide over guide members 83, 84 and 85.

In FIGURE 5 the front and rear dies are shown assembled preparatory to receiving molten lead or other similar low melting point alloy from the pot. Front die 80 is recessed at 97 to receive an insert 98 having an internal cavity 99 for receiving and holding a clip 100 which will be embedded in the lead wheel weight. It will be understood that the recess 97 and the insert itself 98 may be varied in order to hold the clip in any desired position. The die cavity 102 is formed substantially entirely within the front die half 80. An upper covering lip 103 on each rear mold half increases in width from a point of minimum width where the dies meet as shown in FIGURE 5 to a point of maximum width as shown as the left hand end of the die body 90 in FIGURE 7. The lip is curved to receive the overhang portion of the clip 100 as shown in FIGURE 5. The contour of the rear die halves is substantially smooth and uninterrupted as shown in FIG- URE 7 and the die cavity is formed substantially entirely in the front die half.

Rear die 86 is dovetailed at 104 to receive an insert or sprue cutter plate 105 best seen in FIGURES 6 and 7. The cutter is secured to the die half at 106 and has an inlet aperture 107 for the admission of lead to the die cavity. Nozzle 16 is pressed against gate 108 formed jointly by the rear dies. More than a single gate could be used and its location varied. It will be understood that right rear die 87 has a similar inlet aperture 107, best seen in FIGURE 2, so that when the dies are in engage- .inent there will be two inlet apertures opening into the position. Front die block 40 is in its rearward position and handle 30 has been moved as far to the left as possible. By moving handle 30 to the right the front die moves forward due to the sliding action of projection 54 in bottom recess 52. As earns 44 and 46 move towards the rear die block, cam rollers 81 and 82 in grooves 72 and 74 respectively will force the rear die halves 86 and 87 toward engagement in a direction transverse to the path of movement of the front die block. Usually the camways 72 and 74 will be so proportioned that the rear dies abut each other and the front die makes contact with them at substantially the same time. That portion of the crank 56 between pivot 32 and projection 54 will then be in approximately direct alignment with the force exerted by-the' injected metal so that the dies will not separate during injection. The operator then slips a clip 100 down the clip guide 88 and actuates the pump mechanism.

It will be understood that the pump actuating mechanism is conventional and accordingly is not described in detail.

The injected metal will quickly freeze but there will be a gate orsprue extending from the body of the casting through the hole 107 in the sprue cutter plate 105.

When the handle member 30 is moved to the left, the retraction of earns 44 and 46 will cause the rear die halves 86 and 87 to slide outwardly or transversely to the direction of movement of the front die half. This transverse movement will shear the sprue. As the front die retracts the cast lead wheel weight which is carried in the cavity 102 of the front die half will drop in to the discharge bin '18 along the chute 17. By inclining the front die half 80 with respect to the horizontal as shown in FIGURE 3, the wheel weight will drop of its own weight into the discharge bin without the necessity of an expensive ejector mechanism.

While I have shown and described a preferred embodiment of my invention, it will be understood that many variations may be made without departing from its essential spirit. For example, I contemplate that a further swinging movement may be imparted 'to the front die. As the front die block retracts an upward swinging action may be imparted to the die so that the cavity is exposed to theoperator's view. The operation and location of the coolant lines will be largely a matter of choice and must be worked out by actual operation. The temperature to which the metal in the pot is heated will of course be a determining factor.

I claim:

1. A method of moldingobjects in a molding assembly having at least three mold members including at least one front mold member and at least two rear mold members, said rear mold members being movable generally toward and away from one another, said front mold member being movable toward and away from the rear mold members, said method including the steps of forming a mold cavity to be filled by moving the rear mold members into engagement with the front mold member in coordination with the movement of said front mold member, injecting molten metal into the mold cavity through at least one of said rear mold members to thereby form an object having a sprue extending into said one rear mold member, and shearing the sprue by moving the rear mold members generally away from one another.

2. The method of claiml characterized in that the mold member in which the sprue is formed is moved at an angle substantially transversely to the longitudinal axis of the sprue.

3. The method of claim 1 further characterized the sprue cutting movement of the mold member in which the sprue is formed occurs in response to movement of the front mold member.

' 4. A method of molding objects in a molding assembly having at least three mold members including at least one front mold member and at least two rear l'l'lOldTllElIl'.

bers, said rear mold members being movable generally toward and away from one another and said front mold member being movable toward and away from the rearmold members, said method including the steps of forming a mold cavity to be filled by moving the rear mold members into engagement with the front mold member in coordination with the movement of said front mold member, injecting molten metal into saidcavity through said rear mold members to thereby form an object having sprues extending into said rear mold members, and shearing the sprues by moving the rear mold members generally away from one another.

5.'The method of claim 4 characterized in that the mold member in which the sprue is formed is moved at an angle substantially transversely to the longitudinal axis of the sprue.

6. A method of molding objects including the steps of providing a three part molding. assembly composed of two rear mold members movable generally toward and away from one another in a generally horizontal plane and a front mold member movable generally transversely to the direction of movement of-the rear mold members, forming a mold cavity to be filled by moving the rear mold members into engagement with the front mold member, injecting molten metal into the mold cavity through at least one of the rear mold members to thereby form an object having a sprue extending into said one rear mold member, permitting the molten metal in the cavity to solidify, and simultaneously shearing and ejecting the sprue by moving the rear mold members generally away from one another.

7. The method of molding of claim 6 further characterized in that the molded object is gravitally ejected.

8. A method of molding composite objects in a molding assembly having at least three mold members, including at least one front mold member and at least two rear mold members, said rear mold members being movable generally toward andaway from one another and said front mold member being movable generally toward and away from the rear mold members, said method including the steps of forming a mold cavity to be filled by moving the mold members into molding engagement about a mold insert, injecting molten metal into the mold cavity through at least one. of said rear mold members to thereby form a composite object having a sprue extending into said one rear mold member, and shearing the sprue by moving the rear mold members generally away from one another.

'in at least one of the rear mold members, the axis of the gate being disposed at an angle to the path of movement'of the mold member in which it is formed whereby retracting movement of said gated mold member causes shearing of the sprue formed in the gate.

10. The molding assembly of claim 9 further charin that Y acterized in that the gate terminates at the cavity defining surface in a knife edge.

11. An automatic sprue severing mold assembly for molding wheel weights and the like, said mold assembly including at least one front mold member and at least the injection passages and mold cavity in a knife edge sopositioned as to shear the sprue-when the rear mold memtwo rear mold members-formed and adapted when in engagement to define a mold cavity, each of said rear mold members having an injection passage opening into the mold cavity, and knife edges at the junctions of the mold cavity andinjection passage so positioned as to shear the sprues extending into the passages when the mold members move in a disengaging direction, the injection passages being co-extensive over a portion of their length remote from the knife edges.

12. An automatic sprue severing mold assembly for molding wheel weightsand the like, said mold assembly including at least one front mold member and at least two rear mold members formed and adapted when in engagement to define a mold cavity, said rear mold members having injection passages extending through sprue shearing members carried by the rear mold members which define a portion of the mold cavity, each of said sprue shearing members terminating at the junction of hers move in a disengaging direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,582,252 Dodson Apr. 27, 1,595,316 Sampson Aug. 10, 1926 1,939,960 Durwig Dec. 19, 1933 1,956,870 Mayer May 1. 1934 2,316,298 Strun'k Apr. 13, 1943 2,332,856 Kalajian Oct. 26, 1943 2,718,032 Harvey Sept. 20, 1955 2,821,756 Powell Feb. 4, 1958 2,863,188 Harrison Dec. 9, 1958

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