US3804152A

US3804152A - Low pressure die casting apparatus

Info

Publication number: US3804152A
Application number: US00268903A
Authority: US
Inventors: W Cook; J Carlsen
Original assignee: DIMO HOLDINGS Ltd LLANDOWLAIS
Current assignee: DIMO HOLDINGS Ltd LLANDOWLAIS
Priority date: 1971-07-01
Filing date: 1972-07-03
Publication date: 1974-04-16
Anticipated expiration: 1991-04-16
Also published as: JPS548166B1; FR2143924B1; DE2231856A1; GB1399838A; FR2143924A1; DE2231856B2; IT965869B; CH556706A; SE393548B

Abstract

A low pressure die casting apparatus has one or more furnaces each with a feed duct through the cover, through which molten metal is forced by gas pressure. A die placed in co-operation with a feed duct thereby receives a charge of metal. The entire die mounting structure is arranged to be movable relative to the or each furnace in separate vertical and horizontal modes so that a die can be raised clear and to one side of an associated furnace. The die mounting structure and/or furnace may be movable and the horizontal motion is conveniently made by pivoting about a vertical axis.

Description

United States Patent [191 Cook et al.

[ LOW PRESSURE DIE CASTING APPARATUS [75] Inventors: William Joseph Cook, Greenford;

Jon Erik Marius Carlsen, Newport, both of England 73 Assignee: DIMO Holdings Limited of Llandowlais Works, Cumbran,

Monmouthshire, England 22 Filed: July 3, 1972 [21] Appl. No.: 268,903

[30] Foreign Application Priority Data July 1, 1971 Great Britain 30847/71 [52] US. Cl....'.- 164/306, 164/323 [51] Int. Cl 322d 17/06 [58] Field of Search 164/119, 129, 130, 136, 164/306, 323

[ 56] References Cited UNITED STATES PATENTS 3,410,332 11/1968 Woodburn et a1 164/306 X 8/1958 Sylvester 164/119 3,804,152 Apr. 16, 1974 FOREIGN PATENTS OR APPLICATIONS 1,238,700 7/1971 Great Britain 164/306 1,949,520 8/1970 Germany 164/136 2,037,652 4/1971 Germany.... 164/119 644,194 7/1962 Canada ..164/306 81,646 1/1919 Germany 164/119 Primary Examiner-J. Spencer Overholser Assistant Examiner-John E Roethel Attorney, Agent, or Firm-Young and Thompson [5 7] ABSTRACT A low pressure die casting apparatus has one or more furnaces each with a feed duct through the cover,

through which molten metal is forced by gas pressure.

A die placed in co-operation with a feed duct thereby receives a charge of metal. The entire die mounting structure is arranged to be movable relative to the or.

each furnace in separate vertical and horizontal modes so that a die can be raised clear and to one side of an associated fumace.- The die mounting structure and/or furnace may be movable and the horizontal motion is conveniently made by pivoting about a vertical axis.

15 Claims, 8 Drawing Figures PATENTEDAPR 16 m4 SHEET 2 [1F 4 PATENTEU P 1 5 SHEET 3 OF 4 LOW PRESSURE DIE CASTING APPARATUS This invention relates to metal casting apparatus and in particular to a structure for mounting a die or die assembly on a furnace of a low pressure die casting apparatus.

It has been proposed in our British Pat. No. 1,238,700 to provide a die mounting structure for a low pressure die casting apparatus in which the platens carrying the die parts can be pivoted about a vertical axis away from over the furnace. However, there is still some supporting structure remaining over the furnace, restricting access, and the platens'can only co-operate with one furnace and vice-versa.

It is an objectof this invention to provide a die supporting structure which can be mounted independently of a furnace and which can be withdrawn completely clear of the furnace with which it is arranged to operate. It is a further object of some forms of the invention to provide a die supporting structure which can be used in conjunction with more than a single furnace and one which can support more than a single pair of platens that can be used alternately or in conjunction with several furnaces at a time.

According to the present invention there is provided a low pressure die casting apparatus comprising a furnace and a die supporting structure for holding a die over the furnace in co-operation with a feed duct from the cover thereof, the furnace and the entire die sup,- porting structure being capable of relative disengagement at least laterally, the lateral movement being substantially independent of any further disengaging action.

This disengagement facility may be achieved in several ways. In preferred forms the furnace is fixed and the die supportingstructure is vertically and laterally movable. This is conveniently effected by pivotally mounting the structure on a vertical column laterally offset from the furnace,so that the dies can be swung from over the furnace to a position clear of the latter. The column itself may be movable vertically, by means of a supporting jackfor example, to raise and lower the die supporting structure.

vIn its simplest form the die supporting structure includes a single platen unit, i.e., one pair of upper and lower platens on which respective die parts are mounted and which close together for the actual casting (over the furnace) and separate for release of the cast article, which, in .this case may be laterally clear of the furnace. In preferred modified forms the structure may include a plurality of laterally separate platen units. With this arrangement, while one platen unit is co-operating with the furnace the or each other platen unit is laterally clear of the furnace. Thus while one article is being cast another is being removed from its die, and the furnace is more continuously in use:

Alternatively there can be provided at least one fur- .ther furnace, vertically and horizontally fixed as the first mentioned furnace, and similarly co-operable with and disengageable from the die supporting structure. With a die supporting structure having a single platen unit, the latter may be selectively brought into engagement with either orany of the furnaces and have an intermediate position laterally clear of said furnaces. Thus ,while one furnace is being recharged or repaired the other can be used. With two or more platen units there are preferably the same number as there are furnaces and either they all co-operate simultaneously or while one platen unit is disposed over its associated furnace the other, or at least-one other, is laterally clear of its associated furnace. I

It would be possible to have the die supporting structure fixed and the furnace or furnaces movable or even have both movable, for example the furnaces for a short distance vertically and the die supporting structure horizontally.

In a preferred construction the die supporting structure is in the form of a frame with vertical guide columns extending between upper and lower plate members. An upper, movable platen is slidable on the columns between the upper and lower plate members, and the latter may serve as, or support, a fixed lower platen. The upper and lower plate members have lateral extensions fixed to the vertical column supported beside the furnace. The column can rotate about its vertical axis and is vertically movable, by means of a hydraulic jack for example. Means, such as a pneumatic or hydraulic ram, for actuating the upper platen are preferably mounted on the upper plate member and one or more piston rods project down through the upper plate memthrough the duct and nozzle into the die. The movable platen, carrying on its underside a half-die to cooperate with another half-die on the lower platen is moved into a lowered position for casting in synchronism. with the molten metal injections and is subsequently raised, carrying the cast article, which is cleared in known manner.

For changing the dies or other operations on the frame or furnace where it is inconvenient for the frame to be over the furnace, the jack is operated to raise the vertical column and with it the upper and lower plate members acting as cantilever arms carrying the whole frame. This brings the lower part of the frame clear of the feed duct and it can then be pivoted with the column about the latters axis clear of the furnace. The whole die can then be replaced without anyone having to work over the furnace.

It is preferred to use this construction for large structures, whereas the version described in British Pat. No. l,238,700 is considered more suitable for smaller structures.

The invention may be performed in various ways and some constructional forms thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a part sectional elevation of a die mounting structure in conjunction with a furnace,

FIG. 2 is a diagrammaic plan view of the structure of FIG. 1,

FIGS. 3 to 6 are diagrammatic plan' views of other die mounting structures and furnace arrangements according to the invention;

FIG. 7 is a part sectional elevation of the arrangement of FIG. 6, and

.FIG. 8 is a part sectional elevation of a further die mounting structure and furnace.

The die mounting structure of FIG. 1 has a base 1 on which is mounted a furnace 2. This may be of conventional design and will not be described further. Beside the furnace is a pillar 3 upstanding from the base 1 and guiding by means of brackets 4 a vertical column 5 whose lower end is supported by a jack 6. The column 5 can be raised and lowered to a limited extent by this jack and can rotate about its vertical axis.

A frame generally designated7 is supported by this column 5 and can be positioned, as shown in full lines in FIG. 2, over the furnace 2, or to one side of the furnace 2 as shown in dotted lines in FIG. 2.

The frame 7 comprises a lower plate 8 and an upper plate 9 both substantially rectangular and between which extend vertical guide rods 10. The

plates

8 and 9 are held rigidly spaced apart and have re-inforced

lateral extensions

8a and 9a respectively whose ends are formed as bosses in which the vertical column 5 enters and is fixed. The frame thus rotates with the column 5 arms supporting the whole frame. An upper platen 11 slides on the guide rods and is actuated by means of a hydraulic or pneumatic cylinder 12 mounted on the upper plate 9. This piston rod 13 of this cylinder extends vertically downwards through the upper plate 9 to connect with the platen 11. The lower plate 8 may serve as a fixed lower platen or have a further platen securely mounted thereon. The upper platen has a range of movement as illustrated between the full and dotted line positions.

For use, an upper die member (not shown) is fixed to the underside of the movable platen 11 and a lower die member (also not shown) is fixed on the lower platen 8 and a die setting operation is carried out. A feed duct 14 extends through an opening in the top plate 15 of the furnace and when the frame 7 is swung over the furnace and lowered into an operative position bythe jack 6, the feed duct co-operates with a nozzle 16 leading to the lower half-die. The half-dies are moved repeatedly together and in synchronism with.

this molten metal is moved-by gas from the melting pot to the die supported in the die mounting structure. When the upper half-die is raised the cast article is carried with it in known manner and removed by conventional means.

The devices for supplying gas under pressure to the furnace and the melting pot may be conventionally arranged and are not shown.

Whenthe die mounting structure provided by the frame is to be moved to the inoperative position from over the furnace 2 the frame 7 is simply raised by actuation of the jack 6 to break the connection between feed duct and nozzle and it is then free to swing to that new position. 1

It will be understood that instead of fixing the frame to the column 5 the bosses may be such as to allow the frame to rotate on the column, which need then only be vertically movable.

In FIGS. 3 to 6 are illustrated in diagrammatic plan view modified die mounting structures and/or modified furnace arrangements. Similar references, with indices where necessary when parts are duplicated, indicate similar parts.

IN FIG. 3, the base 1, furnace 2 and supporting pillar 3 are the same, but the die mounting structure comprises two

frames

7 and 7 set substantially at right angles. They are rigidly interconnected by webs 8b (not visible) and 9b corresponding to the

extensions

8a and 9a. Thus either

frame

7 or 7 can be set over the single furnace 2 for die casting, while the other frame is swung to one side. In the figure, the frame 7 is moved to the left hand side when inoperative and the frame 7" to the right hand side. With some castings it may be convenient to use the frames in alternation, so that while one article is being cast, another is being removed well clear of the furnace.

In FIG. 4 a column 5 is supported in similar manner between two

furnaces

2 and 2" but carries a single frame 7. This can be swung through substantially a 1 arc to co-operate with either furnace as desired. In an intermediate position the frame is clear of both furnaces. This apparatus can be used like the one of FIGS. 1 and 2, with the. beneficial addition of a reserve furnace which can be serviced and recharged while the other is operating.

FIG. 5 is in effect a combination of FIGS. 3 and 4, having'two furnaces 2' and 2" and two

frames

7 and 7" pivotally supported from a column 5 between the furnaces. The frames being set substantially at right angles can co-operate alternately with the furnaces, frame 7' with furnace 2' (as shown) and frame 7" with furnace 2".

In the apparatus so far described, the pivoting movement is only semi-rotary (through approximately or I80") and the die supporting structure being entirely to one side of the supporting column requires that column to have massive support. A balanced arrangement is shown inFIG. 6 with symmetrically opposed furnaces 2" and frames 7". Here the frames will co-operate simultaneously with the furnaces and be moved clear together. A preferred form of column for this arrangement is shown in FIG. 7. i

The column of FIG. 7 comprises a fixed vertical pillar 17 having an axial bore 18 forming an oil duct, the inlet 19 to which is radial near the base of the column. The duct 18 opens into a cylindrical recess 20 at the top of the pillar 17 which houses a vertically movable piston 21. The piston rod 22 extends upwardly through an end cap 23 to terminate in a thrust bearing 24 which rotatably supports a sleeve 25 by engaging an upper end plate 26 thereof. The sleeve embraces the upper part of the pillar l7 and the interconnecting

webs

8c and 9c between the frames, through the centres of which the sleeve is entered, are welded or otherwise secured thereto. Thus the frames 7" and sleeve 25 can pivot through a full 360 about the fixed pillar l7 and can be raised and lowered by the hydraulic jack built-into the top of the pillar.

It will be understood that there could be more than two furnaces and/or more than two die supporting frames pivoted on a common column, the furnaces for example being set in an annular or part annular array with the column at the centre, the radius of the array being such as to allow clear spaces between adjacent furnaces in which to register non-operative die structures. Further possible arrangements are a linear array of furnaces with intermediate columns each carrying single platen units (as of FIGS. 1, 2 and 4), an L-shaped die supporting structure (as of FIGS. 3 and S) or a balance d die supporting structure (as of FIG. 6). Except for the end ones, the furnaces can then each be served by two separate die structures.

In FIG. 8 there is illustrated apparatus similar to FIG. 7 but with the additional facility of the furnaces, only one of which is shown, being rotatable about the central column. When use is made of this facility the die supporting structure can be rendered non-rotatable by locking pegs 27 entered through the sleeve 25 and engaging in axially parallel grooves 28 in the pillar 17. These grooves allow the sleeve and die structure to be raised and lowered as before.

The furnaces 7" are mounted on a turntable 29 which can rotate about a heightened base 30 of the pillar 17. The outer periphery of the turntable 29 is fitted on the underside with rollers or wheels 31 that run on an annular track 32 centred on the pillar axis and a roller bearing 33 is provided between the base 30 and the surrounding inner periphery of the turntable.

It will be understood that the other embodiments described can also readily be modified to have rotary furnaces, although not through the full 360 as with the balanced arrangement. Also, it is not essential to have the die supporting structure rotatable when the furnaces can be so moved.

It is furthermore possible in each case to give the vertical movement to the furnaces instead of or in addition to the die supporting structure. For this, the furnaces may be supported by jacks.

The rotary movement for all embodiments may be motorised, although in most cases it will be practical to swing the die structure and/or furnaces by hand. It will also often be convenient to provide stops for arresting the die structures and furnaces in correct vertical registry.

Instead of pivoting the die supporting structures, or rotating the furnaces, they may be arranged to move in another mode, for example on rails or other linear guides, the die structures to and from a single furnace, or along a row of spaced furnaces and the furnaces below a single die structure or beneath a row of spaced die structures.

We claim:

1. A low pressure die casting apparatus comprising a furnace, a generally vertical feed duct from the cover thereof, and a die supporting structure for holding a die over the furnace in co-operation with said feed duct, wherein the improvementcomprises a first mounting for the furnace and a second mounting for the die supporting structure laterally clear of and separate from the furnace, and means for moving at least one mounting for vertical engagement and disengagement of the diewith the feed duct and, independently of such vertical movement, for lateral displacement between furnace and die supporting structure in an arc centred on one of said mountings.

2. Apparatus according to claim 1, wherein the first mounting maintains the furnace at a fixed level and the second mounting permits the die supporting structure to be vertically movable.

3. Apparatus according to claim 1, wherein the second mounting maintains the die supporting structure at a fixed level and the first mounting permits the furnace to be vertically movable.

4. Apparatus according to claim 1, wherein the first mounting maintains the furnace at a fixed horizontal location and the second mounting permits the die supporting structure to be laterally movable.

5. Apparatus according to claim 1, wherein the second mounting maintains the die supporting structure at a fixed horizontal location and the first mounting permits the furnace to be laterally movable.

6. Apparatus according to claim 2, wherein the second mounting includes a vertical column whose axis is the pivot axis for the lateral displacement and which is vertically movable to raiseand lower said structure.

7. Apparatus according to claim 1, and comprising at least one further furnace carried by the first mounting and co-operable with and disengageable from the die supporting structure, similarly as the first mentioned furnace.

8. Apparatus according to claim 1, wherein the die supporting structure includes a single platen unit.

9. Apparatus according to claim 1, wherein the die supporting structure includes a plurality of laterally separate platen units.

10. Apparatus according to claim 9 wherein said platen units are laterally stationary within the entire'die supporting structure.

.11. Apparatus according to claim 10, wherein the platen units are arranged in the die supporting structure so that when one platen unit is co-operating with the furnace another platen unit is laterally clear of the furnace. v

12. Apparatus according to claim 7, wherein the die supporting structure includes a single platen unit selectively co-operable with any of said furnaces, said platen operating with an associated furnace another platen unit is laterally clear of its associated furnace.

15. Apparatus according to claim 13, wherein the furnaces are so disposed and the arrangement of the platen units is such that all the platen units co-operate simultaneously with associated furnaces and have intermediate positions clear of said furnaces.

Claims

1. A low pressure die casting apparatus comprising a furnace, a generally vertical feed duct from the cover thereof, and a die supporting structure for holding a die over the furnace in cooperation with said feed duct, wherein the improvement comprises a first mounting for the furnace and a second mounting for the die supporting structure laterally clear of and separate from the furnace, and means for moving at least one mounting for vertical engagement and disengagement of the die with the feed duct and, independently of such vertical movement, for lateral displacement between furnace and die supporting structure in an arc centred on one of said mountings.

6. Apparatus according to claim 2, wherein the second mounting includes a vertical column whose axis is the pivot axis for the lateral displacement and which is vertically movable to raise and lower said structure.

10. Apparatus according to claim 9, wherein said platen units are laterally stationary within the entire die supporting structure.

11. Apparatus according to claim 10, wherein the platen units are arranged in the die supporting structure so that when one platen unit is co-operating with the furnace another platen unit is laterally clear of the furnace.

12. Apparatus according to claim 7, wherein the die supporting structure includes a single platen unit selectively co-operable with any of said furnaces, said platen unit having at least one intermediate position laterally clear of said furnaces.

13. Apparatus according to claim 7, wherein the die supporting structure includes a plurality of laterally separate platen units and there are the same number oF furnaces as there are platen units.

14. Apparatus according to claim 13, wherein the furnaces are so disposed and the arrangement of the platen units is such that when any one platen unit is co-operating with an associated furnace another platen unit is laterally clear of its associated furnace.