FR2650519A1 - Shaking-out (knocking-out) installation - Google Patents

Abstract

The invention relates to a shaking-out (knocking-out) installation which will apply particularly to the foundry field. In order to separate the foundry sand from moulded components contained in a tank 2, the shaking-out installation of the present invention provides for the use of a tipper 1 of the tank 2 with progressive action as well as a shaking-out table 3 with high separating power by means of alternating movements. The progressive action is due to a turning movement 2 slowed when the said tank 2 is in the course of turning over. The shaking-out table 3 has a screen surface 10, the bars 11 of which are in the form of a double slope. The invention relates to metallurgy or all industries requiring the separation of components from a certain volume of the environment surrounding them, for example sand.

Description

 The invention relates to a stall installation which will find its application in particular in the field of foundry.

 Among the various processes known in the mechanical engineering industry for obtaining parts, foundry remains one of the most efficient techniques for the production of parts in series.

 After developing the alloy, we proceed to casting in molds. There are different kinds of molds, however the most used is the foundry sand mold.

 This mold is made of a tray that is filled with sand, taking care to create an imprint in the sand corresponding to the part to be produced. This impression is produced by a core of expanded polystyrene or any other suitable material.

 There are special machines capable of placing the core and filling the foundry tank with sand, compacting it by a vibratory movement; These machines prepare the molds in series, which are then conveyed to the casting station. There, the operator pours the molten alloy, contained in a pocket, into the mold where gradually the core of fusible material is replaced by the alloy which solidifies as it cools.

At the end of this casting operation and when the alloy is completely solidified, it is advisable to recover the casting, this is the role of the release. For this, there are currently several techniques. One solution is to use trays with a retractable bottom. In this case, the bottom is removed when the tray is placed on a stall table. The table is formed by a long grid animated by a vibratory movement maintained at least by a motor. Thus, the container is constantly shaken and, in addition, a movement of movement of the container is created, which makes it possible to place them one after the other on the release table. The tremors have
the purpose of which is to unhook the sand from the walls of the room and from the tank and in addition, to promote the elimination of sand through the meshes of the grid of the table.

 This technique has some drawbacks.

First of all, it is necessary to have bins at the bottom
retractable, which is not the general case and then the stall table is very noisy and painful for the environment.

Another solution used is to use a
device capable of turning the foundry tank over the
stall table. In this respect, an overhead crane can be used provided with a device for gripping the foundry tank with off-center fixing. During the first phase of handling, the turning device is locked, which keeps the container in an upright position. When
it is placed above the release table, the locking mechanism is released and the off-center attachment causes its sudden reversal.

 the defect of the overturning technique is the almost instantaneous unloading of the contents of the foundry tank. Indeed, the stall table is in a fraction of a second covered by the sand and the castings. The fact that the stall table is heavily loaded requires significant power from the vibratory drive mechanism and the intense efforts involved also have repercussions on the environment. In addition, the castings present on the stall table hide the table grid and therefore, the foundry sand is more difficult to remove, which requires using a very long stall table given its reduced efficiency. .

 The parts are then collected at the end of the release table by a squeegee system or an electromagnet if the shape of the parts and their nature allow it.

 Currently, stalling is a delicate phase in foundry operations and it is a very costly operation, significant in terms of floor space occupied and the most difficult to automate.

 The main object of the present invention is to present a stall installation, intended to be integrated in a foundry and which has a very high efficiency in its work. In particular, it is compatible with the use of traditional foundry tanks, and the release table is relatively very short. The release device of the present invention is compact and forms a homogeneous whole and it should be added that the vibrations necessary for the release table are zero. Therefore, the nuisance is very limited.

 Another advantage of the present invention is to present a release device which can easily be automated. Indeed, the installation comprises an entry point which consists in introducing a foundry tank into elevation means, a first outlet where the molded parts are delivered free of sand and a second outlet which collects the sand in a tank for example. In this way, no human intervention is necessary to carry out the various stall and recovery operations.

 Simple but robust in design, the stall installation of the present invention, thanks to its compactness, its savings in labor and its ability to be automated, should find a wide outlet in the industry where it can be found. adapt to the existing environment.

 Other objects and advantages of the present invention will become apparent during the description which follows which is, however, only given for information and which is not intended to limit it.

 The stall installation which will find its application in the field of- foundry for separating sand from the molded parts contained in a tank or container at the end of the casting is characterized by the fact that it comprises - a tank spillway or progressive action container, - a release table with strong separating power.

The invention will be better understood on reading the following description accompanied by attached drawings, among which
FIG. 1 shows diagrammatically the main elements of the stall installation according to the present invention,
FIGS. 2a, b, c, d and e represent the different phases of the operation of the bin overflow device according to the present invention,
FIGS. 3a and 3b show diagrammatically a preferred method of constructing the screening surface of the release table viewed from the front and from the side,
FIG. 4 illustrates a method of construction of the release device in side view,
- Figure 5 shows in front view this same embodiment of the stall installation according to the present invention.

 The present invention relates to a stall installation which will find its application in particular in the field of foundry.

 The techniques for forming metal parts by molding an alloy are widely known. It is an economical process for large series and which allows parts with very complex shapes to be obtained.

 The first step is to make a mold in which the part will be cast. For this, a tray or chassis is generally used which is filled with foundry sand, taking care to leave an imprint corresponding to the shape of the part to be produced. This imprint materializes in the form of a core made of a suitable material such as polystyrene or other. During casting, the molten metal gradually fills the imprint. After cooling, the part must be recovered and for this, the foundry sand must be removed. It is the release operation. When a chassis or tray with a retractable bottom is used, you can choose the bottom and place the chassis on a release table with high vibrating power. Strong mechanical shocks cause the sand to crumble, which is eliminated through the perforated surface of the table.

 The most general solution consists in using an overhead crane system, which causes the container and its contents to overturn over a stall table. Always thanks to a vibrating movement, the sand is partially eliminated through the orifices of the table while the pieces are directed towards an outlet. The defect of this process lies in the sudden overturning of the contents of the chassis or tray. In fact, the release table suddenly gets filled with all of the content of the molding material and the removal of sand is more difficult given the large quantities. of material brought into play during the initial phase and moreover, the pieces tend to mask the orifices of the table with greater difficulty in removing the sand.

 Specifically, the purpose of the stall installation of the present invention is to allow the separation of foundry sand and molded parts to be achieved very quickly with relatively limited forces involved, in particular without vibrations and a workstation surface. reduced work.

 Figure 1 shows schematically the release system according to the present invention. It comprises first of all a spillway (1) intended to overturn a tank (2) filled with foundry sand and molded parts above a stall table (3).

 The overflow (1) is progressive, that is to say that one avoids suddenly overturning the entire contents of the tank (2) on the release table (3) but on the contrary, the operation is carried out in such a way that we start initially by pouring the foundry sand then the molded parts. This has big advantages. First of all, the release table is not massively filled and therefore the inertias and efforts involved are not intense.

Then, the fact of initially depositing the sand on the stall table makes it possible to eliminate it quickly. The molded parts do not mask the orifices of the table as is traditionally encountered and therefore the sand can flow freely with a large flow.

 It will not be necessary to provide a long screening distance on the stall table since the parts are initially already re-cleaned by the overflow device (1).

 In its operation, according to a preferred embodiment of the invention, the overloader (1) quickly raises and turns the tank (2) substantially to 900 then submits the latter to a slowed down rotary movement, that is to say during of the critical phase of the overthrow. I1 appears that there is a maximum spillage of the contents of the tank (2) when the latter is being overturned; this overturning point is a function of the relative differential friction of the materials contained in the tank and of the slope of inclination of the wall of the tank.

 Consequently, by controlling the speed of overturning - when the inclination is close to this level, the flow rate of the overturning which is spread is limited. Likewise, it can be seen that the foundry sand tends to pour out of the tank (2) more quickly than the larger molded parts.

 Figure 2a shows schematically the first phase of an operation of pouring the contents of a tank (2) lined with foundry sand (4) and a molded part (5). The bin is initially placed on a platform. (6) elevator which has a spout (7).

 The overflow device (1) of the invention has a system for guiding the lifting platform (6). According to the present invention, a guiding doubt is used, firstly the lower part of the platform (6) is guided in a vertical movement by a first guide path (8). Secondly, the upper part of the platform (6) is guided in a plunging movement by a second guide path (9).

During the entire overturning operation of the tank (2), the latter is fixed to the platform (6).

 Initially, during its upward movement, the lifting platform (6) rises vertically as illustrated in FIG. 2b. Indeed, the guide path (9) for the plunging movement is in the form of a stick and therefore, in the vertical part of the stick, the paths (8 and 9) are parallel, which has the effect of creating a vertical movement of the platform (6).

 On the other hand, when the upper guide of the lifting platform (6) arrives in the curve of the butt 9) as illustrated in FIG. 2c, the divergence encountered causes the inclination of the platform (6) and therefore of the tank ( 2-).

 When the spout (7) of discharge is horizontal as illustrated in Figure 2d, its end reaches a zero speed, which results in an angular speed of rotation for the renyersement of the tank (2) extremely reduced. The content and more particularly the foundry sand (4) extends over the spout (7) and the continuation of the upward movement of the platform (6), as illustrated in FIG. 2e, causes the gradual flow of the sand foundry (4) at the end of the spout (7) then. the pouring of the molded parts (5). Another advantage of this technique is that the molded parts are not dropped suddenly on the release table.

 To complete this effect, a pendulum curtain (18) suspended from the fixed frame (6) can help to slow down the falling speed of the parts and favor their distribution on the release grid (10).

 According to the present invention, a motor member is used which creates a regular upward movement applying to the lower guide point of the platform (6). We could for example use a hydraulic cylinder device or other, driven by a constant speed of movement. However, mechanical movements with variable speed motors could be implemented.

 Although already very effective thanks to the progressive overturning of the tank by the spillway of the invention, the stall installation also includes a stall table with high separating power, consequence of its operating principle which is based on that of a feeder with reciprocating movements and is shown diagrammatically in FIG. 3. Although of relatively small dimensions, the release table (3) has a large screening surface (10). Indeed, according to the invention, 'to increase. the screening surface (10), the bars (11) which constitute it are uneven. Thus, the developed surfaces of the separation bars (11) are larger than on a flat table, this device increases the passage of foundry sand. More favorably, the bars (11) of the screening surface (10) are arranged in a double slope, as illustrated in FIGS. 3a and 3b. This has several advantages, in particular to quickly remove the sand present on the surface by a spreading movement promoting flow.

In addition, the screening table is very rigid, placed on rollers (19), sloping and subjected to movement.
(20) alternative, forward / backward, of displacement which causes a directed trajectory of exit of the parts and which makes it possible to advance the parts forward while the sand flows through the grid (10). It should be noted that this technique is very insensitive to loads and overloads which can be very significant since the effort to be overcome is only a rolling effort, unlike traditional vibrating tables.

Figures 4 and 5 show respectively in side view and in front view a preferred mode of -construction screening plant according to the present invention. The spillway (1) proper comprises a cage
(12) formed of assembled profiles in which the lifting platform (6) carrying a container (2) operates. The platform
(6) has a discharge tank (7) supported by lateral arms (i3). In addition, it is guided in its lower part by a set of rollers (14) fitted into vertical uprights in sections. On the other hand, the upper part is guided by a set of rollers (15) fitted into a guide path (9) in the form of a butt.

 The screening surface (10) of the release table (3) illustrated in dotted lines in FIG. 5, is inclined to direct the molded loose parts towards a lateral outlet (16). For this, the release table is supported by rollers (17) placed on a slope. The rollers (1-7) have a fixed positioning and provide support for the release table driven in an alternative translational movement. While traditionally, the parts are also shaken in a vertical direction, according to the present invention, only a horizontal movement is used, which minimizes the nuisance in the environment. When small parts must be molded, it is advantageous to use a series of recesses on the screening table to promote the evacuation of these light parts.

 It can be seen that the complete automation of the installation of the present invention can easily be achieved by providing for automatic introduction and evacuation of the tanks (2) in the lifting platform (6) and also by adopting a recovery system. output parts (16).

 Other implementations of the present invention, within the reach of ordinary skill in the art, could also have been envisaged without departing from the scope thereof.

Claims (10)

 1. Unhooking installation which will find its application in the field of foundry to separate the sand from the parts contained in a tank (2) at the end of the casting, characterized by the fact that it comprises - a spillway (1) of tank (2) with progressive action, - a release table (3) with strong separating power.  2. A release device, according to claim 1, c a r a c t e r i s e in that the overturning movement of the spillway (1) causes and promotes the flow of foundry sand (4) and molded parts (5).  3. Stall installation; according to claim 1, c a r a c t é r i s e by the fact that the overflow (1) quickly raises the tray, returns the tray (2) to 900 substantially and then subjects the tray (2) to a slowed down rotary movement.  4. Release device, according to claim 1, characterized by the fact that the overflow (1) is formed by an elevating platform (6) on which is placed the tank (2), guided in its lower part in a vertical movement (8) and in its upper part in a plunging movement (9).  5. A release device according to claim 4, c a r a c t e r i s e in that the lifting platform (6) is driven by a regular upward movement applying to the lower guide point.  6. Unhooking installation according to - claim 4, c a r a c t é r i s e in that the guide path for the movement-plunging (9) is in the form of a butt.  7. Unhooking installation according to claim 1, c a r a c t é r i s e in that the table 'unhooking (3) has bsrreaux (11) differences in level.  8. Unhooking installation according to claim 7, c a r a c t é r i s e in that the unhooking table (3) has a screening surface (10) with bars (11) in double slope.  9. release device, according to claim 1, characterized by the fact that the release table (3) is animated by an -movement (20) alternating front / rear, which causes a directed trajectory of output of parts.  10. Unhooking installation according to claim 1, c a r a c t é r i s e by the fact that the unhooking table (3) has a screening surface (16) whose bars (11) are inclinedlongitudinal towards an outlet (16).