DE1067985B - - Google Patents

Description

GERMAN

kl. 31b 12

INTERNAT. KL. B 22 C

PATENT OFFICE

Z5407VI / 31b

REGISTRATION DATE: FEBRUARY 25, 1956

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: OCTOBER 29, 1959

The invention relates to a sandblowing machine with automatic control of the sand exit from the or the supply of compressed air to the sand container.

Sandblasting machines operated with compressed air for the production of foundry cores and molds are known. There are two different designs and modes of operation of sandblasting machines, namely on the one hand the actual sandblowing machines working with an air-sand mixture and on the other hand, the so-called sand shooting machines, in which the molding sand jerks into the molding box is printed.

The previously known sand shooting machines are usually larger with an air inlet valve Equipped opening, which is designed in some cases as a ring slide, whereby the compressed air directly acts on the sand surface. The ring valve, which is either a rotary valve or a piston valve works, surrounds the sand storage container, its inner insert for receiving the core sand mixture serves.

In a known sandblowing machine, the sand is charged by means of compressed air, controlled sand feed valve, which is located at the outlet of the compressed air and sand container or is arranged at the upper end of the mouthpiece. This independent control of the sand and pressure outlet has the disadvantage that the piston sleeves working in the sense of a valve within the Sand filling have to work and give rise to malfunctions.

The object of the invention is to avoid these disadvantages and a To create a machine that enables the economical production of foundry cores and molds.

This was mainly achieved by using the known in principle automatic control of the sand outlet from the or the compressed air supply to the sand container for Control of the compressed air supply to a blower container, which can be moved axially within the machine head is arranged and that communicating with the compressed air line openings in the machine head in the blowing position are opposite openings in the blowing container acting as a piston slide. In the lowest position of the blower, the openings in the machine head are from the Covered sliding surface of the blower.

Another feature of the invention is that the axially movable conical blow container has two Has cylindrical sliding surfaces, with the flat side of the lower as a simply acted upon pressure piston acts and is larger in diameter than the diameter of the upper sliding surface.

Sandblowing machine

for filling mold and core boxes with automatic control

of the sand outlet

Applicant:

Central Institute for Foundry Technology,
Leipzig W 34, Gerhard-Ellrodt-Str. 24

Wolfram Hempel, Leipzig,
has been named as the inventor

In order to loosen the core sand mass located in the blow tank from the wall, the upward movement of the blow container, the volume of the cavity between the blow container and the machine head is reduced and the cavity that is being formed Compressed air through small openings in the blow tank blown out.

The sliding surfaces of the blower or that of the machine head are with one or more Equipped seals. The cylindrical outlet of the blower container expediently protrudes into the intended outlet Nozzle or the like into it. The attachment of sand wiper rings is also advantageous, as is that the downward movement of the blower 'is effective by a spring or equivalent components is supported.

An exemplary embodiment of the invention is described below with reference to the drawing.

The piston underside 4 of the conical blower container 3 is joined by a control valve (not shown) Compressed air is applied. Due to the large piston area and the relatively large feed line cross-section the blower is pushed up very quickly. Thereby the air gets into the cavity 10 between the blow container 3 and the machine head 1 slightly compressed, through small holes 11 of the blower container 3 is blown and the core sand mass is thereby pressed off the wall of the blower container 3. The blower 3 then strikes a collar of the machine head 1 so that the holes 9 of the blower 3 with the bores 2 of the machine head 1 face each other.

Due to the rapid upward movement of the blower 3, the core sand mass located in it remains because of their persistence

901 6 * 0/115

Claims (6)

and is slightly compressed by the conical blow container 3. The inertia force of the core sand mixture is also used to convey the core sand into the core box or the like. The compressed air consumption is thus significantly lower than with conventional machines with the same function. At the same time, the upward movement of the conical blow container 3 removes those in the upper part 1. Springs 8 are tensioned and the exhaust hole 16 for the blow container 3 is closed by the control edge of the blow container 3. At the moment when the bores 9 of the blower 3 with the bores 2 of the machine head 1 face each other, compressed air enters the blower 3 from the storage container (not shown) and presses the core sand mass through the nozzle 7 into one of a table on the blower plate Nozzle 7 pressed core box, not shown. At the same time, compressed air enters the cavity 10 between the blow container 3 and machine head 1 through very small slots 12 of the blow container 3, which in turn pushes the core sand mixture off the container inner wall through many small holes 11 in the blow container 3 and thus the sand on its Way into the core box supports. If the core is blown and the core box or the like is filled with core sand mixture, the core box prevents the compressed air from quickly escaping into the atmosphere, so that the compressed air flowing in from the storage container passes through the cavity 13 above the - caused by the filling of the core box Core sand mass in blow container 3 and also the cavity 10 between blow container 3 and machine head 1 fills. The pressure in these two cavities 13 and 10 increases and acts on the one hand on the projecting circular ring surface of the piston top on the flange 4 of the container 3, which together are larger than the surface acted upon by the piston bottom 4. After a short time, a pressure equalization occurs between the piston 4 of the blower container 3, which is acted upon by compressed air from below, and the pressure acting from above on the above-mentioned surfaces. The springs 8 in the upper machine part 1, which are still tensioned when the blower 3 is raised, relax and press it downwards. This closes the bores 2 of the machine head 1, and the supply of compressed air is blocked. At this moment, the exhaust bore 16 is also released, and the compressed air enclosed in the blow tank 3 can flow out through this in connection with the small bores 17 of the intermediate flange 18. Now the piston bottom 4 of the conical blower 3 is vented by the control valve, not shown, so that the compressed air acting on the piston bottom 4 does not push the blower 3 back up. Before the core box (not shown), pressed against the nozzle 7 by the table, returns to its starting position, the pressure still present in the blow container 3 is equalized. PaTEXTaNS: ■ [; ('C.il Ii: 1. Sandblowing machine for filling mold and core boxes with automatic control of the sand outlet from the compressed air supply or supply to the sand container, characterized in that to control the compressed air supply to the blow tank (3) inside the machine head (1) is arranged to be axially movable and that the with the compressed air line in connection standing openings (2) in the machine head in the blowing position openings (9) in the as a piston valve facing the acting blower containers. 2. Sand blowing machine according to claim 1, characterized in that the sliding surfaces of the machine head (1) in the lowest position of the blower (3) the openings (2) in the machine head (1) cover. 3. Sand blowing machine according to claim 1 and 2, characterized in that the axially movable conical blow container (3) has two cylindrical sliding surfaces, the flat side of the lower than acts simply acted upon pressure piston and is larger in diameter than the diameter of the upper sliding surface. 4. Sand blowing machine according to claim 1 to 3, characterized in that when moving upwards of the blower container (3) the volume of the cavity (10) between the machine head (1) and the blow tank (3) is reduced, so that the compressed air formed therein by small openings (11) flows into the blower container (3). 5. Sand blowing machine according to claim 1 to 4, characterized in that the lower, cylindrical The outlet of the blower container (3) protrudes into the nozzle (7) attached to the machine head (1). 6. Sand blowing machine according to claim 1 to 5, characterized in that in support of the Downward movement of the blow container (3) after the blown core in the machine head (1) springs (8) or the like are effective. Considered publications:
German patent specification No. 568 318. 1 sheet of drawings © 909 640/116 10:59