JPS62101347A - Method for packing molding sand into vacuum shaping flask - Google Patents

Abstract

PURPOSE:To oscillate an oscillation table to be imposed with a pattern and molding flask not only in a vertical direction but also in a horizontal direction and to thoroughly pack the sand into the recess in the transverse direction of the pattern by using air dampers in place of air springs to support said table. CONSTITUTION:Compressed air is evacuated from the air dampers 2 to suck a film onto the surfaces of a pattern board 9 and pattern 12 in tight contact therewith; thereafter the molding flask 8 is imposed via the film on the board 9. One set corresponding to the adjacent dampers 2 of 4 pieces of regulating valves 5 is so adjusted that the set pressure thereof is different from the set pressure of the other one set of the valves 5. A hopper 14 is thereafter turned to the position right above the oscillation table 6 and the compressed air is supplied to the dampers 2. Then the dampers 2 expand and the table 6, the board 9 and the flask 8 ascend so that the top surface of the flask 8 contacts the bottom surface in the aperture at the bottom end of the hopper 14. The table 6 is thoroughly oscillated in the vertical direction and in the horizontal direction as well by the unbalance of the supporting characteristics of the dampers 2 when molding sand is packed into the flask 8 and the table 6 is oscillated by an oscillating body 7. The sand is thus thoroughly packed into the recess 11 as well.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for filling a molding flask with molding sand in a vacuum molding method.

(Prior art) Conventionally, when filling a molding flask with molding sand in a vacuum molding method, a vibration table supported by a plurality of air springs and equipped with an oscillator at the center of its lower surface was placed below a molding sand supply hopper. The flask is placed on the vibrating table via a model plate with a model and a film, and compressed air is supplied to the air spring to inflate it, thereby making the top surface of the flask The oscillator is brought into contact with the lower surface of the hopper, molding sand is charged into the flask, and then the oscillator is activated (for example, Japanese Patent Publication No. 58-29176).

However, in the above-mentioned filling method, the vibration direction of the vibration table is mainly vertical, so if the model has four horizontal parts, the recesses are not filled with sand enough, and as a result, the shape of the product is distorted. Defects often occur.

(Objective of the Invention) The present invention has been made in view of the above circumstances, and it is an object of the present invention to enable a vibration table to sufficiently vibrate not only in the vertical direction but also in the horizontal direction, and to sufficiently vibrate the four horizontal parts of the model. The purpose is to fill it with sand.

(Structure of the Invention) Hereinafter, the present invention will be described in detail based on embodiments. The drawings show an implementation device of the present invention, in which a base frame (1) is fixed on a base (not shown), and the base frame (1) is fixed to a base (not shown). Air dampers (2) made of elastic members that can be expanded and contracted by supplying and exhausting compressed air are disposed at the four corners of the upper surface of 1). Each of said air dampers (2) communicates with a source of compressed air (4) via a respective conduit (3), said respective conduit (3)
A pressure reducing valve (5) is provided in the middle. The air damper (2) supports a vibration table (6), and near the center of the lower surface of the vibration table (6) is an oscillating body (of a mechanism that generates vibrations due to the unbalanced inertial force of the rotating body). 7)
is installed.

A model plate (9) is attached on the vibration table (6), and a casting flask for vacuum molding is mounted on the model plate (9).
8) is placed with a film (not shown) interposed therebetween.

A horizontal recess (11) is provided on the central upper surface of the model plate (9).
) is attached to the model (12).

In addition, (13) is a "J". (14) is a foundry sand supply hopper equipped with a sand gate (15) at its lower end opening, and the hopper (14) is attached to a support (not shown). The vibration table (6) is rotatably supported in the horizontal direction via a rotary support arm, and is horizontally rotatable between a position directly above the vibration table (6) and a standby position on the side.

(Function) To explain the process of filling the casting flask (8) with molding sand using the device configured as described above, compressed air is exhausted from the air damper (2), and then the model plate (9) and the model are (12)
After a film (not shown) is brought into close contact with the surface of the model plate (9), the flask (8) is placed on the model plate (9) with the film interposed therebetween. Next, among the four pressure reducing valves (5), set one set of pressure reducing valves (5) corresponding to the adjacent air damper (2) so that its set pressure is different from that of the other set of pressure reducing valves (5). Adjust to Thereafter, the hopper (14) is rotated from the standby position to a position directly above the vibration table (6). When compressed air is supplied from the compressed air source (4) to the air damper (2) in this state, the air damper (2) expands, causing the vibration table (6), model plate (9) and casting flask (8) to expand. ) are raised together, and the upper surface of the flask (8) comes into contact with the lower surface of the lower end opening of the hopper (14). At this time, a pair of adjacent air dampers (
The pressure of 2) is different from that of the other set of air dampers (2). Next, open the sand gate (15) and open the hopper (
Fill the molding sand into the flask (8) from step 14), and then
The vibration table (6) is activated by operating the oscillator (7).
) to increase the degree of sand filling in the flask (8). At this time, the vibration table (6) vibrates not only in the vertical direction but also in the horizontal direction due to the unbalanced support characteristics of the air damper (2). After the predetermined time has passed, the gate (1
5) and stop the operation of the oscillator (7)), exhaust the compressed air from the air damper (2), and lower the vibration table (6), model plate (9), and flask (8). , thereby releasing the contact between the upper surface of the flask (8) and the lower surface of the lower end opening of the hopper (14).

Next, the hopper (14) is rotated back from the position directly above the vibration table (6) to the standby position. Thereafter, the inside of the flask (8) is communicated with a vacuum pump (not shown) to reduce the pressure, and the upper surface of the flask (8) is covered with a film to solidify the sand under reduced pressure. Next, the flask (8) holding the solidified sand is cut out from the model plate (9) and model (12) and sent to the next process.

The above operations are considered as one cycle, and the same cycle is repeated thereafter.

(Effects of the Invention) As is clear from the above description, the present invention unbalances the support characteristics of each air damper by adjusting the pressure reducing valve when inflating a plurality of air dampers with the pressure of compressed air. This causes the vibration table to vibrate not only in the vertical direction but also in the horizontal direction. Therefore, according to the present invention, the sand in the flask is sufficiently shaken not only in the vertical direction but also in the horizontal direction. Occurrence is prevented.

In the embodiment, two adjacent air dampers are considered as one set to create a pressure difference between them and another set of air dampers, but two air dampers located at diagonal positions are considered as one set. A pressure difference may be provided between the other set. Furthermore, the four air dampers may each have different support characteristics, and furthermore, only one of the four air dampers may have different support characteristics.

[Brief explanation of drawings]

The drawing is a partially cutaway sectional view of an implementation device of the present invention.

Claims (1)

[Claims] A vibration table (6) supported by a plurality of air dampers (2) and having an oscillator (7) attached to the center of its lower surface.
A flask (8) is placed on top of the flask (8) via a model plate (9) and a film, and compressed air is supplied to the air damper (2) at different pressures to cause the upper surface of the flask (8) to vibrate. Table (6
), the casting flask (8) is filled with molding sand, and the oscillator (7) is activated. A method for filling molding sand in a vacuum molding flask, characterized in that: