GB2059836A

GB2059836A - Moulding machine

Info

Publication number: GB2059836A
Application number: GB8019444A
Authority: GB
Original assignee: Sintokogio Ltd
Current assignee: Sintokogio Ltd
Priority date: 1979-10-09
Filing date: 1980-06-13
Publication date: 1981-04-29
Also published as: FR2467029A1; FR2467029B1; DE3021592A1; CH647701A5

Abstract

Moulding sand in cope and drag moulding flasks 50, 18 is squeezed by plates 56, 8 after compaction effected by compressed air introduced into the said flasks. Means 76, 32 are provided for interrupting the communication between a moulding sand discharging port 72, 28 of a sand reservoir 68, 24 and a moulding sand charging passage 71, 27 of a blow plate device, thereby to prevent the moulding sand and compressed air from flowing back into the sand reservoir during the air compacting operation. The interrupting means may be constituted by slide plates 76, 32 disposed slidably between the above mentioned discharging port and charging passage and provided with a communication port 79, 36 for selectively providing communication between the discharging port and the charging passage. Alternatively rotary valves may be used as the interrupting means. <IMAGE>

Description

SPECIFICATION Moulding machine The present invention relates to a moulding machine in which moulding sand in cope and drag moulding flasks is squeezed by squeeze plates after being compacted by compressed air blown into the moulding flasks.

This type of moulding machine is disclosed in our Japanese Patent Laid-Open Publication No. 51930/1979. In this moulding machine, the moulding sand often flows back together with compressed air into the sand reservoir, while the moulding flasks are charged with compressed air for compacting the moulding sand in the moulding flasks, which seriously hinders the moulding operation. It is, therefore, necessary to maintain the pressure in the sand reservoir at a level higher than that of the air flowing through the moulding sand, if this flow back is to be prevented.

The pressure in the sand reservoir, is usually reduced to 0.2 to 1.0 atm after the moulding sand has been charged into the flask. In order to prevent the moulding sand from flowing back into the sand reservoir, it is necessary to maintain the pressure in the sand reservoir at least higher than 5 to 6 atm, because the compressed air which has to flow across the bed of the moulding sand is usually pressurized up to 5 to 6 atm. In consequence, the consumption of compressed air is increased, and a considerably long time is required for the pressure rise in the sand reservoir. This is uneconomic and reduces productivity.

We have now designed a moulding machine which can obviate the above-described problems.

Thus, the present invention consists in a sand moulding apparatus, in which compressed air can be applied to a sand reservoir to displace sand from the reservoir through a squeeze plate to a pattern where compaction can take place, and in which compressed air can be applied through the squeeze plate, other than via the sand reservoir, to carry out the compaction; the path from the sand reservoir to the squeeze plate being interruptable to prevent blow-back to the reservoir during compaction.

The invention is further illustrated, by way of example, by the accompanying drawings, in which Figure 1 is a longitudinal sectional view of a moulding apparatus; Figure 2 is an enlarged sectional view of a lower slide gate and an expandable seal incorporated in the apparatus shown in Fig. 1; Figure 3 is an enlarged sectional view of an upper slide gate and expandable seal incorporated in the apparatus shown in Fig. 1; and Figure 4 is a longitudinal sectional view of another type of apparatus.

Referring first to Figs. 1 to 3, a reference numeral 1 denotes a gate-shaped frame including a pair of opposed columns 3 standing upright from a base 2 and an upper frame 4 interconnecting the upper ends of the columns 3. An intermediate frame 5 extends between the columns 3 at portions of the latter somewhat closer to the lower end of the frame 1. A lower squeeze cylinder 6 is attached to the upper side of the intermediate frame 5 and extending upward therefrom. The squeeze cylinder 6 has a piston rod 7 to the end of which is attached a lower blow plate 10 having an upper plate constituting a lower squeeze plate 8 and an internal sand charging passage 9. The lower squeeze plate 8 has a hollow body having an internal air chamber 11, and has a plurality of vent holes formed in its upper surface communicating with the air chamber 11.Also a plurality of small bores 1 3 for charging the moulding sand are formed in the lower squeeze plate 8 across its thickness from the upper to lower sides. The charging passage 9 joins the small bores 1 3 and a charging pipe 14 which extends outwardly from the lower blow plate 10.

The air chamber 11 is connected to a twoway valve 17, by means of an air passage 1 5 formed at one side of the lower blow plate 10, and a rubber hose 16. The two way valve 1 7 communicates with a compressed air source (not shown).

A drag flask 18, large enough to accommo date the lower squeeze plate 8, is positioned above the lower squeeze plate 8 (when the plate is in its lowermost position). The drag flask 1 8 has a peripheral chamber 1 9 and vent holes formed in its inner wall in communication with the chamber 1 9. The drag flask is fixed to the piston rods 22 of cylinders 21 one disposed at each side of the squeeze cylinder 6. This arrangement provides vertical movement for the drag flask. A two-way valve communicating at one of its sides with the chamber 1 9 and with the atmosphere at its other end, is attached to the outer wall of the drag flask 18.Reference numeral 24 denotes a lower moulding sand reservoir having a sand receiving port 26 at its upper side and a sand discharging port 28 at its lower side.

The sand receiving port 26 is provided with a gate valve 25, while the sand discharging port 28 is communicatable with the charging port 27 of charging pipe 1 4. A sliding member 30 is attached to the end of each of the ports 27 and 28. Each sliding member 30 is provided with an annular groove, as is clearly shown in Fig. 2, in which groove is disposed an expandable sealing member 29 which can expand and contract as the compressed air is charged into and out of the groove. More specifically, as compressed air is supplied to the back side of the expandable sealing member 29 through a passage 31, the expandable sealing member 29 expands outward to make close contact with the side surface of a slide plate 32, which will be mentioned later.Conversely, as the compressed air is relieved from the expandable sealing member, the latter is contracted inwardly from the sliding surface of the sliding member 30, so that the expandable sealing member 29 is not worn by friction against the lower slide plate 32 as the latter is slid.

The lower slide plate 32 is attached to the end of a piston rod 35 of a cylinder 34 which in turn is attached through a bracket 33 to the upper face of the base 2 so as to extend upward therefrom. Thus, the lower slide plate 32 is movable in the vertical direction by the operation of the cylinder 34, into and out of the slight gap between the sliding members 30 at the ends of the ports 27 and 28. A communication port 36 is formed at an upper portion of the lower slide plate 32 so as to provide selectively communication between the ports 27 and 28.

A reference numeral 37 denotes an inlet valve which communicates at its one end with the source of compressed air and at its other end with the side wall of the lower reservoir 24. A relief valve 38 is connected to the side wall of the reservoir 24 opposite to the inlet valve 37. A match-plate type pattern plate 39, having an internal chamber 41, runs on a roller conveyor 40 above the drag mould flask 1 8. The pattern plate 39 has a pin bore 42 formed at its rear end for engagemnet with a pin 46. The pin 46 is attached to the end of a piston rod 45 of a travel cylinder 44 in turn attached to the upper surface of a column 43, so as to travel along the roller conveyor 40 as the travel cylinder 44 is actuated. The pattern plate 39 is provided with small vent holes 47 in its upper and lower surfaces.Patterns 48 are mounted substantially in the mid portion of the pattern plate 39 on the both surfaces of the pattern plate 39, and are provided with a relief port 49 formed in their side walls in communication with the internal chamber 41.

A cope moulding flask 50 for use with the drag moulding flask 1 8 is positioned above the pattern plate 39 and is fixed by a pair of supporting columns 3 via a supporting member 51. The cope moulding flask 50 is provided with a peripheral chamber 52 and a suitable number of small vent holes formed in its inner wall for communication with the chamber 52. Also, a two-way valve 55 communicatable through a hose 54 with the chamber 52 is connected to the outer wall of the cope moulding flask.

An upper blow plate 58, having a lower plate constituting an upper squeeze plate 56 and having an internal sand charging passage 57, is disposed above the cope moulding flask 50. The upper blow plate 58 is attached to the end of a piston rod 60 of an upper squeeze cylinder 59, which in turn is attached to the upper frame 4 from which it extends downwardly.

As in the case of the lower squeeze plate 8, the upper squeeze plate 56 is a hollow member having an internal air chamber 61. A plurality of vent holes 62 for communication with the air chamber 61 is formed in the lower side of the upper squeeze plate. At the mid portion of the upper squeeze plate 56, is a plurality of small bores for charging the sand. These bores extend through the thickness of the squeeze plate 56 from the upper to the lower sides. The sand passage 57 is in communication with the bores 63 at its one end, while the other end of the passage communicates with a charging pipe 64 which projects outwardly from the upper blow plate 58.

An air passage 67 formed at one side of the upper blow plate 58 communicates with the two-way valve 66 through a rubber hose 65.

A reference numeral 68 denotes an upper said reservoir having at its upper side a moulding sand receiving port 70 provided with a gate valve 69 and at its lower side a moulding sand discharging port 72 communicatable with the charging port 71 of the charging pipe 64. A sliding member 74 is attached to the end of each of the sand charging ports 71 and 72. Each sliding member 74 contains an expandable sealing member 73. The expandable sealing members 73 expand or contract in response to the application or removal of compressed air. More specifically, as the compressed air is applied to the back side of each expandable sealing member 73 through each air passage 75, the member 73 expands outwards to make a close contact with the side surface of an upper slide plate 76, which will be mentioned later.Conversely, as the compressed air is removed, each expandable sealing member 73 contracts inwardly from the sliding surface of the sliding member 74 so that the member 73 is not worn by friction during sliding of the upper slide plate 76. The upper slide plate 76 is fixed to the end of a piston rod 78 of a cylinder 77 attached to the upper frame 4, from which it extends downwardly. In this way, the slide plate 76 is moved through the slight gap formed between the slide members 74. The upper slide plate 76 is provided in its upper part with a communication port 79 which selectively permits the ports 71 and 72 to communicate with each other.

A reference numeral 80 denotes an inlet valve which communicates at its one side with the compressed air source and at its other side with the side wall of the upper sand reservoir 68. A relief valve 81 is attached to the side wall opposite to the inlet valve 80.

The moulding sand is designated by a refer ence numeral 82. The internal chamber 41 of the pattern plate 39 may be provided with a horizontal partition wall to prevent interference between the flow of air entering from the upper and lower sides.

In the apparatus described above, separate lower and upper sand reservoirs 24 and 68 are provided to charge the drag and cope moulding flasks 18, 50 independently. This arrangement, however, is not essential and a single sand reservoir, preferably having two discharge ports may be used.

The moulding machine described may be operated as follows.

The cylinder 6 is actuated to raise the drag flask 1 8 into contact with the pattern plate 39, which beforehand was set in the moulding position. Subsequently, the drag flask 18 together with the pattern plate 39 is moved as a unit to come into contact with the lower face of the cope flask 50 which is kept stationary and covered at its upper side with the upper squeeze plate 56. Then, the squeeze cylinder 6 is actuated to raise the lower squeeze plate 8 attached to the end of its piston rod 7 to the level of the lower end of the drag flask 1 8 to close the lower opening of the latter. Simultaneously, the cilinder 34 is actuated to lift the slide plate 32 so as to bring the charging port 27 of the lower blow plate 10 into communication with the discharging port 28 of the lower sand reservoir 24.Simultaneously, the upper cylinder 77 is actuated to raise the upper slide plate 76, to permit the charging port 71 of the upper blow plate 58 and the discharging port 72 of the upper sand reservoir 68 to communicate with each other.

At the same time, compressed air is charged into the air passages 31, 75 to expand the expandable sealing members 29, 73 to make them contact closely the upper and lower slide plates 32, 76, respectively.

Thereafter, the gate valves 25, 69, the relief valves 3881 and the two-way valves 17, 66 are closed, while the two-way valves 23, 55 attached to the outer walls of the drag and cope moulding flasks 18, 50 are opened to the atmosphere. Also, the inlet valves 37, 80 are opened to introduce compressed air into the lower and upper sand reservoirs 24 and 68, thereby to charge the sand 82 into the drag and cope flasks 18, 50. This occurs through the communication ports 36, 79, the charging ports 27, 71 the charging passages 9, 57 and the small bores 13, 63. The compressed air charged together with the sand into the drag and cope flasks is relieved to the outside through vent holes 20, 53, internal chambers 19, 52 and then through the discharge port 47, the internal chamber 41 and the relief port 49 of the pattern plate 39.Subsequently, the two-way valves 23, 55 and the inlet valves 37, 80 are closed and, at the same time, the relief valves 38, 81 are opened to relieve the compressed air from the lower and upper sand reservoirs 24, 68 and, further, to relieve the compressed air from the air passages 31, 75 to permit the expandable sealing member 29, 73 to contract. At the same time, the cylinders 34, 77 are reversed to move the upper and lower slide plates 32, 76 to interrupt the communications between the charging ports 27, 71 and the discharging ports 28, 72. Then, compressed air is supplied again into the air passages 31, 75 to expand the expandable sealing members 29, 73 to make the latter closely contact the sliding surfaces of the slide plates 32, 76.

Thereafter, the two-way valves 17, 66 in communication with the compressed air source (not shown) are opened to supply compressed air into the cope and drag flasks 18, 50 via the rubber hoses 16, 65, the air passages 15, 67, the air chambers 11, 61 and the vent holes 12, 62, thereby to condense and to compact the moulding sand on the surface of the pattern plate 39 to increase the compactness and hardness of the sand.

The compressed air supplied into the drag and cope flasks does not flow back the sand reservoirs 24, 68 because the communications between the charging ports 27, 71 and the discharging ports 28, 72 are interrupted by the lower and upper slide plates 32, 76, respectively. Instead, the compressed air is forced to flow through the moulding sand to compact it around the surface of the pattern plate 39. The compressed air then flows to the outside through the discharge port 47, internal chamber 41 and the relief port 49.

After compaction of the sand at the surfaces of the pattern plate 39, the two-way valves 17, 66 are closed and the two-way valves 23, 55 attached to the outer walls of the lower frame 1 8 and the upper frame 50 are opened to the atmosphere. At the same time, the compresed air is discharged from the air passages 31, 75 to contract the expandable sealing members 29, 73 to disengage them from the sliding surfaces of the slide plates 32, 76.

Then the lower squeeze cylinder 6 and the upper squeeze cylinder 59 are actuated to drive the squeeze plates 58 and 56 into the drag and cope flasks 18, 50 to squeeze the sand in these flasks to compact it around the squeeze plates. As a result of the squeezing, in combination with the effect of the foregoing compacting operation, a mould having a uniform hardness is formed.

Subsequently, the squeeze cylinders 6, 59 are operated to retract their piston rods to move the lower and upper squeeze plates 8, 56 away from the surfaces of the mould and, at the same time, the cylinders 21 are operated to lower the drag moulding flask 1 8 together with the pattern plate 39. After leaving the pattern plate 39 on the roller conveyor 40, the drag flask 1 8 is further lowered to the starting position. Thereafter, the pattern plate 39 placed on the roller conveyor 40 is moved from the moulding position to the retracted waiting position by the operation of the travel cylinder 44. Thereafter, the cylinders 21 are actuated again to raise the drag flask 1 8 carrying the drag mould to set the latter to the cope mould held by the cope mould flask 50.

Then, the squeeze cylinder 6 is actuated to raise the lower squeeze plate 8 into contact with the lower surface of the drag mould held by the drag flask 50. Thereafter, the upper squeeze cylinder 59 is actuated to lower the upper squeeze plate 56 to force out the cope and drag moulds closed downwardly from the drag and cope moulding flasks 18, 50. Then, the squeeze cylinder 6 is reversed to lower the lower squeeze plate 8 carrying the cope and drag moulds thereon to the lower end of this stroke. Finally, the cope and drag moulds placed on the lower squeeze plate 8 are moved laterally from the latter, thereby to complete one cycle of moulding operation.

The supply of sand into the lower and upper reservoirs 24, 68 is made through the receiving ports 26, 70 by opening the gate valves 25, 69, after relieving the compressed air from the reservoirs 24, 68 by opening the relief valves 38, 81 and closing the inlet valves 37, 80.

Although in the foregoing description the drag moulding flask 1 8 and the pattern plate 39 were moved upwards as a unit to meet a stationary cope moulding flask 50, this arrangement is not essential. For instance, it is possible for the drag and cope flasks 18, 50 to be moved upwards and downwards, respectively, into contact with the pattern plate 39 which is in this case kept stationary.

Furthermore, it is possible to use valves 129, 1 68 incorporating rotary valves as shown in Fig. 3, in place of the slide plates 32, 76 in order to open and close the discharging ports 28, 72 of the sand reservoirs 24, 68.

As has been described, according to the invention, it is not necessary to raise the pressures in the upper and lower sand reservoirs to prevent the compressed air and the moulding sand from flowing back to the reservoirs, during the compacting operation, which is effected by forcibly passing compressed air through the moulding sand in cope and drag flasks. Thus the present invention can contribute to the saving of energy and to a good production of moulds, as well as to an improvement in productivity.

Claims

1. A sand moulding apparatus, in which compressed air can be applied to a sand reservoir to displace sand from the reservoir through a squeeze plate to a pattern where compaction can take place; and in which compressed air can be applied through the squeeze plate, other than via the sand reservoir, to carry out the compaction; the path from the sand reservoir to the squeeze plate being interruptable to prevent blow-back to the reservoir during compaction.

2. An apparatus according to claim 1, having a ported side plate between a discharge port of the reservoir and a charging port to the squeeze plate, such that relative linear movement between the ports can interrupt or open the path.

3. An apparatus according to claim 1, having a rotary valve between the sand reservoir and the squeeze plate for interrupting or opening the path.

4. An apparatus according to claim 2, in which the discharge port and the charging port each has a sealing member which bears against the slide plate under pressure of compressed air to render the path air tight, such that in the absence of this pressure the sealing members are relaxed allowing the relative linear movement.

5. Apparatus according to claim 1, substantially as herein described with reference to any one of the accompanying drawings.

6. A sand moulding apparatus having a drag flask and squeeze plate and a cope flask and squeeze plate, and a pattern; the pattern and each flask and squeeze plate constituting an apparatus according to any one of the preceding claims.

7. An apparatus as defined in claim 6, but having a single sand reservoir for supplying both the drag and cope squeeze plates.

8. A moulding machine comprising: a moulding flask; a blow plate device including a squeeze plate provided with a plurality of vent holes for jetting compressed air into said moulding flask and with a plurality of ports for charging moulding sand, said squeeze plate being movable into said moulding flask, and a moulding sand charging passage defined at the back side of said squeeze plate and communicating with said moulding sand charging ports; a pattern plate provided with a plurality of vent holes for relieving air from said moulding flask and adapted to be set in said moulding flask so as to oppose to said squeeze plate across said moulding flask; a sand reservoir provided with a moulding sand discharge port communicatable with said moulding sand charging passage of said blow plate device; and interrupting means adapted to interrupt the communication between said moulding sand charging passage of said blow plate device, when compressed air is jetted into said moulding flask through said vent holes of said squeeze plate.

9. A moulding machine as claimed in claim 8, wherein said interrupting means includes a slide plate slidably disposed between said moulding sand discharging port of said sand reservoir and said moulding sand charging passage of said blow plate device and provided with a communication port for bringing said moulding sand discharging port and said moulding sand charging passage into communication with each other.

10. A moulding machine as claimed in claim 8, wherein said interrupting means include a rotary valve attached to the end of said moulding sand discharging port of said sand reservoir and communicatable with said moulding sand charging passage of said blow plate device.

11. A moulding machine as claimed in claim 9, said interrupting means comprising: a first sliding member attached to the end of said moulding sand discharging port of said sand reservoir; a second sliding member attached to the end of said moulding sand charging passage of said blow plate device; an annular expandable sealing member provided on said first sliding member to oppose to said slide plate; an annular expandable sealing member provided on said second sliding member to oppose to said slide plate; and air passages provided in said first and second sliding members and adapted to cooperate with respective expandable sealing members such that said expandable sealing members are expanded to make close contact with said slide plate as they are expanded by compressed air charged through said air passages.

12. A moulding machine comprising: a drag moulding flask; a lower blow plate device including a lower squeeze plate having a plurality of vent holes for jetting compressed air into said drag moulding flask and a plurality of moulding sand charging ports, and adapted to be moved into said drag moulding flask, and a moulding sand charging port defined by the lower side of said lower squeeze plate and communicating with moulding sand charging ports; a cope moulding flask; an upper blow plate device including an upper squeeze plate having a plurality of vent holes for jetting compressed air into said cope moulding flask and a plurality of moulding sand charging ports, and movable into said cope moulding flask, and a moulding sand charging passage defined by the upper face of said upper squeeze plate and communicating with said moulding sand charging ports;; a match plate having a plurality of relief ports in upper and lower surfaces thereof for relieving air through an internal chamber defined therein from said cope and drag moulding flasks; lifting devices for lifting and lowering said drag moulding flask or said drag and cope mould flasks into a position where said cope and drag mould flasks are superposed to each other with said match plate placed therebetween; sand reservoir means having a first and second moulding sand discharging ports communicatable with respective one of said moulding sand charging passages communicating with said ports of said upper and lower squeeze plates moved into said cope and drag moulding flasks in a superposed position; and interrupting means adapted to interrupt the communications between said first moulding sand discharging port and said moulding sand charging passage of said upper blow plate device, and between said second moulding sand discharging port and said moulding sand charging passage of said lower blow plate device, when the compressed air is jetted into said cope and drag moulding flasks through said vent holes of said upper and lower squeeze plates.

1 3. A moulding machine as claimed in claim 12, wherein said interrupting means include a first slide plate slidably disposed between said first moulding sand discharging port and said moulding sand charging passage of said upper blow plate device and having a first communication port for providing communication between said first moulding sand discharging port and said charging passage; and a second slide plate slidably disposed between said second moulding sand discharging port and said moulding sand charging passage of said lower blow plate device and having a second communication port for providing communication between said second moulding sand discharging port and said moulding sand charging passage of said lower blow plate device.

1 4. A moulding machine as claimed in claim 12, wherein said interrupting means includes a first and second rotary type valve attached to the ends of said first and second moulding sand discharging ports of said sand reservoir and communicatable with said moulding sand charging passages of said upper and lower blow plate devices, respectively.

1 5. A moulding machine as claimed in claims 1 2 to 14, wherein said internal chamber in said match plate is provided with a horizontal partition plate for preventing mutual interference between flows of air relieved through the vent holes in its upper and lower surfaces.

16. A moulding machine as claimed in claims 1 2 to 15, wherein said match plate is movable in the horizontal direction between the moulding position and a waiting position.