US3548922A - Metal-casting apparatus - Google Patents

Description

Q United States Patent 1 1 3,548,922

[72] Inventor Jon Erik Marius Carlsen [56] References Cited c/o Llandowlais Works, oflkfle 8 UNITED STATES PATENTS 2,1 19,242 5/1938 Flammang et a]. 164/309X [211 P 6501846 2 270 340 1/1942 Pritchard 164/309 [22] Filed July 3, 1967 4s Patented m. 22, 1910 FOREIGN PATENTS [32] Priority Mar. 16, 1967 484,659 7/1952 Canada 164/309 [33] Brim Primary Examiner-J. Spencer Overholser [31] 420/67 Assistant Examiner-John S. Brown Attorney-Hall, Pollock & Vande Sande [54] METAL-CASTING APPARATUS 1 v v 12 Claims 5 Dnwing Figs ABSTRACT: A metal-casting apparatus for low pressure die [$2] 0.8. CI 164/309 casting having a die-carrying structure pivotally supported for [51] Int. Cl B22d 17/02 movement to and from an open mouth presented, by a metal- [50] Field of Search 164/309, carrying duct, at the top of the furnace, the vertical position of the pivot axis of the die-carrying structure being adjustable.

8 /26 I II I, 9 I I l I I I II II 5 2 /26 3' 20 224 l ""El 'lj PATENTED UEE22 I970 sum '1 UF 3 O ERIK MARIUS UARLSEN Inventor 1 0K 4 Attorney;

1 METAL-CASTING APPARATUS v This invention relates to metal casting apparatus of thekind used in low pressure die casting. I

Known low pressure die casting apparatus has comprised a structure which includes dies and ancillary mechanism and which is displaceably mounted on the top of a melting furnace. This structure is periodically lifted from the furnace in order that the melting pot may be refilled with metal and, at other times, so that it may be relined. In the operation of replacing the structure, which is heavy, much care must be taken to guide itinto its correct position on the furnace so that leaks may be avoided. Dies of different dimensions and die apertures are commonly required to be used in a die casting apmetal-conducting duct to be used with each die.

This object isachie'ved by the apparatus provided by the invention according to which, in a metal-casting apparatus for low pressure die casting having a melting furnace provided with means for introducing gas under pressure into a melting pot in the furnace and a feed duct, disposed in an opening at the top of the furnace, for carrying molten metal moved by the gas from the meltingpot to a die supported in a superimposed structure, the duct being loosely supported in an upright position by the furnace with its lower end presenting a free open mouth to the metal in the pot and with its upper end disposed to present an open mouth to the interior of the die, the superimposed structure is pivotally supported, for upward movement from its operative casting position on the furnace top into a position to afford access to the duct, by a pivot which is arranged to be adjusted to vary the vertical position of the pivot axis.

The vertical adjustment of the pivot axis of the die-carrying structure solves, in a simple manner the problem of avoiding the use of a multiplicity of ducts.

The adjustability of the pivot axis enables a further advantage to be provided. Instead of, as has hitherto been necessary, arranging that the duct be free from connection to the die, in the apparatus provided by the invention the duct may be formed with a portion attached to and depending from the die, a further portion of the duct which is loosely supported by the furnace top having, at its upper end, a seating adapted to receive the lower end of the duct portion attached to the die.

The invention is illustrated by way of example in the accompanying drawings of a low pressure die casting apparatus in which FIG. 1 is a side elevation, FIG. 2 is a plan view, FIG. 3 is a fragmentary view on an enlarged scale of part of the apparatus shown in FIGS. 1 and 2,

FIG. 4 is a view on an enlarged scaleshowing stops for supporting the die-supporting structure of the apparatus and the melting pot and is connected to a collar 3b which is supported by the shoulder in a countersunk opening 4 in a positioning top plate 5a mounted on the top 5 of the furnace 1. An asbestos gasket 6 is placed between the collar 3b and said shoulder. A woven asbestos rope 5b which seats in a groove 50 on the undersurface of the plate 50 serves to prevent leakage between the plate and the furnace top. The plate 50 is able to move slightly on the furnace top when the structure 2 moves into the casting position, to enable the partsof the duct 3 to align themselves correctly. The portion 3a is fixed to and depends from a fixed half die 7. The portion 3a serves as a connector tube for connecting the bore of the parts 3b and 3c with the moulding space in the fixed half die 7. The portions 3b and 3c may be made as a single integral member. As shown in FIG.

3, the lower end of the portion 3a isarranged to seat onthe f shoulder in a counterbore 11 in the portion 3b. As shown, the cooperating seating surfaces of the two portions 3a and 3b are conical and inclined to the axis of the bore of the duct. An

FIG. 5 is a view, also on an enlarged scale, showing adjusta- 1 ble pivot-carrying means.

Referring to the accompanying drawings, a melting furnace 1 is disposed below a die-supporting structure indicated generally by the reference 2. The furnace is arranged to receive a feed duct 3 and to be supplied, in known manner,

with low pressure air or other gas. The feed duct 3 is arranged to dip into a melting pot disposed in known manner within the furnace. The devices for supplying gas under pressure to the furnace and the provision of a melting pot may be conventionally arranged in well-known manner and are not shown; The feed duct 3 is shown, in FIG. 3, as formed by two separable portions 3a and 3c respectively. The portion 30 dipsinto asbestos gasket, not shown, may be placed between the seatsurfaces may, instead, be provided. The upper end of the duct portion 3a opens to a passage 8 in the fixed half die 7. The bore of the passage 8 has the same diameter as the bore in the duct. The half die 7 is held widely spaced, by spacing bars 109, from a lower fixed platen ,9, which is fixed to a machine table 10, so that a wide gap 12 appears between the half die 7 and the platen 9. The die-supporting structure comprises fixed columns 15 on which a movable platen 116 which carries a moving half die 16, see FIG. 3, is slidably mounted. A top plate 17 is fixedly mounted on the columns 15 and supports a hydraulic ram 18 which has a plunger 19 connected with the movable platen 116. The ram 18 is arranged to reciprocate the platen 116 and the half die 16 and to hold the moving half die adjacent the fixed half die during a casting operation.

It will be observed that, in addition to the wide gap 12, the bars 109, the lower fixed platen 9 and the table 10, are also widely spaced from the duct 3. Thisarrangement facilitates the dispersion of heat from the die and consequently promotes economical and easy operation of the apparatus.

The machine table 10 bears on the furnace top 5 via adjustable stops on the top 5. These stops comprise a body 21 which is fixed t0 the top and an adjustable bolt having a head 22 on which the bottom of the table 10 bears when the diesupporting structure is in its operative casting position. Fixed stops 20 are also provided to limit the downward movement of the table.

. The weight of the table 10 is also partly taken by pivot bearings 25, 26 carried in bearing blocks Y23 and 24. These blocks are vertically slidable in frames 123 and 124 and are adjustable to a desired height by means of screw jacks comprising screws and 126 which constitute a second control means. Worm wheels 127 and 128 are respectively keyed to these'screws and are operable together by a manually actuated worm-carrying spindle 129. The stops 21, 22 are adjustable to provide that the die-supporting structure with the fixed halfdie 7, presses sufficiently firmly against the bearing surfaces on the collar 3b so as to prevent leakage from the duct. The portion 3a may be held by screws or be otherwise attached to the half die 7.

The bearing blocks 23 and 24 are carried by a structure 28 which is rigidly secured to the furnace 1. This structure 28 also supports a hydraulic ram 29 by means of struts 30 and 31. The ram cylinder is pivotally carried in bearings and at the upper ends of the struts 30 and 31 by trunnions 34 and 35 which project from the ram cylinder. The plunger 36 of the ram 29 is linked by a pivot 37 to an arm 38 which is rigid with and extends laterally from the machine table 10 so that the table and the arm 37 form a two-armed lever. The ram 29 and arm 38 are thus adapted to cause the table 10 together with the diesupporting structure to be swung upwards about the common axis of the pivots 25 and 26 in an are centered on the pivot axis, and having both vertical and horizontal substantial components of direction. The movement of the table may be such that it swings through an angle of 90 but an angle of 60 would usually be sufficient.

A hydraulic pump 39 driven by a motor 40 and arranged to deliver into a hydraulic supply tank 41 is provided for the supply of liquid under pressure to the rams 18 and 29 via suitable ducts and control valves arranged in conventional manner. The ram 29, arm 33 and associatedparts comprise a first control means, and it will be seen that with the ram in the position illustrated in FIG. 1 the screws 125, 126 can be operated to adjust the vertical height of the table and the superimposed structure over a limited range of movement from the position in which these parts lie closely adjacent to the top of the furnace, and during this vertical adjustment the axis of the pivots 25, 26, and also the table 10 and the superimposed structure, is constrained against lateral movement.

In the arrangement shown, a gas tight seal is effected between the duct 3 and the top of the furnace by virtue of the arrangement of the parts and the pressure transferred through the half die to the tube 3. A further advantage accrues from the fact that no relative axial displacement of the bore of the passage 8 and the bore of the duct 3such as would interfere with the operation of the furnace can take place.

Each die to be used in the apparatus is alternatively and preferably provided with a duct portion 3a which may be detachable from the half-die 7.

l claim:

l. A metal-casting apparatus for low pressure die casting having a melting furnace provided with means for introducing gas under pressure into a melting pot in the furnace and a feed duct, disposed in an opening at the top of the furnace, for carrying molten metal moved by the gas from the melting pot to a die supported in a superimposed structure, the duct being loosely supportedin an upright position by the furnace with its lower end presenting a free open mouth to the metal in the pot a and with its upper end disposed to present an open mouth to the interior of the die, first means supporting the superimposed structure and permitting concurrent upward and lateral movement of said superimposed structure from its operative casting position on the furnace top into a position to afford access to the duct, and second means for adjusting the vertical position of said superimposed structure relative to its operative casting position independently of the motion imparted by said first means.

2. A metal-casting apparatus as claimed in claim 1 wherein the duct comprises a portion, arranged to be secured to and to depend from a fixed half-die, and another portion which is adapted to extend into molten metal in the furnace and has an upper end arranged to present a seat for the lower end of the first-mentioned portion.

3. A metal-casting apparatus as claimed in claim 1 wherein the duct comprises a portion arranged to be secured to and to depend from a fixed half-die, and another portion which is adapted to extend into the molten metal of the furnace and has an upper end arranged to present a seat for the lower end of thefirst-mentioned portion, the said other portion of the feed duct being carried by a positioning plate which is movable on the furnace top under the influence of the two duct portions when the die-supporting structure moves into its operative casting position.

4. A metal-casting apparatus for low pressure die casting having a melting furnace provided with means for introducing gas under pressure into a melting pot in the furnace and a feed duct, disposed in an opening at the top of the furnace, for carrying molten metal moved by the gas from the melting pot to a die supported in a superimposed structure, the' duct being loosely supported in an upright position by the furnace with its lower end presenting a free open mouth to the metal in the pot and with its upper end disposed to present an open mouth to the interior of the die, pivot means supporting the superimposed structure for upward movement from its operative casting position on the furnace top into a position to afford access to the duct, means for adjusting the vertical position of the pivot axis, the duct comprising a" portion, arranged to be secured to and depend from a fixed half-die, and another portion which is adapted to extend into molten metal in the furnace and-has an upper end arranged to present a seat for the lower end of the first-mentioned portion, and a fixed platen on the pivotal superimposed structure having an opening through which the ductpasses with clearance.

5;A metal-casting apparatus as claimed in claim 4 wherein the fixed half-die is held spaced from the fixed, platen by bars which are themselves spaced from theduct.

6. A metal-casting apparatus for low pressure die casting having a melting furnace provided with means for introducing gas under pressure into a melting pot in the furnace and a feed duct, disposed in an opening at the top of the furnace, for carrying molten metal moved by the gas from the melting pot to a die supported in a superimposed structure, the .duct being supported in an upright position by the furnace with its lower end presenting a free open mouth to the metal in the pot and with its upper end disposed to present an open mouth to the interior of the die, and including first control means for moving the superimposed structure relative to the furnace in a path having substantial vertical. and horizontal components of direction, and second control means for moving the superimposed structure, or a support therefore, in a substantially vertical direction over a limited range of movement from a position in which the said structure or support lies adjacent the furnace.

7. Apparatus as claimed in claim 6, in which the two control means are independently operable.

8. Apparatus as claimed in claim 6, in which the first control means includes a poweroperated hydraulic ram.

Sl. Apparatus as claimed in claim 6, in which the second control means includes a pair of screw jacks mounted at one side of the furnace.

10. Apparatus as claimed in claim 6, in which the second control means is arranged to provide limited vertical movement of the superimposed structure, insufficient in itself to afford the necessary access to the furnace.

11. Apparatus as claimed in claim 6, in which thefirst control means includes a pivotal support for the superimposed structure, at one side of the furnace, and the second control means is arranged to adjust the vertical position of the pivotal support.

12. Apparatus as claimed in claim 11, wherein the superimposed structure is movable about pivots which are arranged to be raised and lowered together in supports mounted on a surface rigid with the furnace.

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