APPARATUS FOR PRODUCING CASTING MOULD PARTS AND COMPRISING AUXILIARY GUIDING MEANS

Abstract: In an apparatus for producing casting mould parts by compacting sand or other like material between a vertical squeeze plate (1) and a vertical swingable plate (2) in a squeeze chamber (3), wherein the swingable plate (2) swings away after the compaction to allow passage of the mould part from squeeze chamber (3) by further forward movement of the squeeze plate (1) and the swingable plate is journalled on a front yoke (4) mounted on guide columns (5) for movement relative to the squeeze chamber (3), a pull yoke (6) is placed behind the squeeze chamber (3) and connected to the guide columns (5). At least two of the guide columns (5) are journalled in a number of guides (7) connected to a fixed part of the apparatus close to the position of the front yoke (4) in the compacting position and the pull yoke (6) is provided with at least one guide (8) journalled on guide columns (9) connected to fixed parts of the apparatus. By this construction the rigidity of the frame structure consisting of front yoke (4), guide columns (5) and pull yoke (6) is increased by the guidance of the pull yoke which prevents movements in a plane perpendicular to the intended movement of the frame structure.

Description: APPARATUS FOR PRODUCING CASTING MOULD PARTS AND COMPRISING AUXILIARY GUIDING MEANS TECHNICAL FIELD The present invention relates to an apparatus for producing casting mould parts by compacting sand or other like material between a vertical squeeze plate and a vertical swingable plate forming movable end walls in a squeeze chamber. The swingable plate can swing away after compaction to allow passage of the mould part from the squeeze chamber by further forward movement of the squeeze plate and the swingable plate is journalled on a front yoke which is in turn mounted on guide columns for movement relative to said squeeze chamber. A pull yoke is placed behind the squeeze chamber and connected to the guide columns. The front yoke, the pull yoke and the guide columns form a relatively rigid frame structure parallel with the longitudinal axis of the squeeze chamber. An apparatus of this kind is e.g. known from EP-231 ,741 , and EP-020,082. BACKGROUND ART In such known apparatuses the pull yoke is only controlled in its movements by the guide columns and accordingly, uneven forces applied to the squeeze plate and the swingable plate, respectively, in connection with differently shaped patterns will cause a deformation of the relatively rigid frame structure consisting of the guide columns and the two connected yokes. In order to reduce such deformation and correspondingly reduce the tilting movement of the swingable plate, it is known, e.g. from EP-231 ,741 , to provide bearings for the guide columns close to the front of the squeeze chamber and close to the back of the squeeze chamber. However, this will not completely prevent a certain tilting movement of the swingable plate during the compacting. DISCLOSURE OF THE INVENTION It is the object of the invention to further reduce such deformation and in accordance with the invention, this is achieved by the provision of means for guiding the pull yoke as indicated in the characterizing part of claim 1. By means of this, the pull yoke is directly guided and supported against movements in a plane perpendicular to the intended movement of the frame structure and accordingly, a more rigid frame structure is achieved providing a more rigid guidance of the swingable plate, in particular preventing a tilting movement, without substantially increasing the dimensions of the apparatus, and without substantially increasing the weight of the moved frame structure consisting of the front yoke, the pull yoke and the guide columns. Preferred embodiments of the invention are set forth in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS In the following detailed part of the present description, the invention will be explained in more detail with reference to the exemplary embodiments of an apparatus for producing casting mould parts according to the invention shown in the drawings, in which Figure 1 shows a schematic side view of an apparatus in accordance with the invention in the compacting position, Figure 2 shows the apparatus in Figure 1 in the extraction position, Figure 3 is a detailed drawing of parts of the apparatus in Figure 1 , Figure 4 is a schematic sketch indicating an embodiment of the invention corresponding to Figure 1 , Figure 5 is a sketch corresponding to Figure 4, showing an alternative embodiment of the invention, and Figures 6, 7 and 8 show alternative constructions for guiding the pull yoke. DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus for producing casting mould parts by compacting sand or other like material is of the type comprising a vertical squeeze plate 1 and a vertical swingable plate 2 forming movable end walls in a squeeze chamber 3. The swingable plate 2 is swingably connected to a front yoke 4 which is mounted on guide columns 5 for movement relative to the squeeze chamber 3. A pull yoke 6 is connected to the guide columns 5 at the ends opposite the front yoke 4. The guide columns 5 are journalled in guides 7 connected to the squeeze chamber 3 close to the position of the front yoke 4 in the compacting position shown in Figure 1 , and the pull yoke 6 is connected to a hydraulic drive unit 11 for moving the frame structure consisting of the front yoke 4, the pull yoke 6 and the guide columns 5, whereby the swingable plate 2 is moved relative to the squeeze chamber 3. In the construction shown in Figures 1 and 2, the pull yoke 6 comprises guides 8 journalled on auxiliary guide columns 9, whereby the movement of the pull yoke 6 is controlled. The auxiliary guide columns 9 are at one end, close to the squeeze chamber 3, connected to the squeeze chamber 3 or other fixed part of the apparatus, and at the opposite end the auxiliary guide columns 9 are fixed to a fixed part of the apparatus, in Figures 1 and 2 shown as a block 12. The movement of the squeeze plate 1 is provided by means of a hydraulic drive unit 10. By the construction shown, the frame structure consisting of the front yoke 4, the guide columns 5 and the pull yoke 6 is relatively compact, increasing the rigidity of this frame structure, and the distance between the guides 7 for the guide columns 5 and the guides 8 for the auxiliary guide columns 9 is close to maximum in the compacting position shown in Figure 1 , in which the forces on the structure is at maximum, and this distance is smaller in the extraction position shown in Figure 2, in which position the forces on the structure are minimal and the rigidity is of minor importance. The apparatus for producing casting mould parts functions in the traditional way, the squeeze chamber 3 being filled with sand and said sand being compacted between the squeeze plate 1 and the swingable plate 2 which are moved into the chamber 3 by means of the hydraulic drive units 10 and 11. After compacting, the hydraulic drive unit 11 moves the swingable plate 2 away from the squeeze chamber 3 and the swingable plate is moved to the position shown in Figure 2 in order to allow passage of the mould part from the squeeze chamber 3 by forward movement of the squeeze plate 1 by means of the hydraulic drive unit 10. The mould parts leaving the apparatus forms a mould string used for mould-string casting as known by a man skilled in the art. Figure 3 shows the essential parts of the apparatus in accordance with the invention, namely the frame structure consisting of the front yoke 4, the guide columns 5 and the pull yoke 6, the guide columns 5 being journalled in guides 7 and the pull yoke 6 comprising guides 8 journalled on auxiliary guide columns 9. In Figure 3, the system is shown in the compacting position and it is clear from this drawing that the front yoke 4 is intimately controlled in its position by the guides 7 and the position of the pull yoke 6 in a vertical plane perpendicular to the movement direction of the pull yoke 6 is intimately controlled by the engagement between the guides 8 and the auxiliary guide columns 9, which are connected to a fixed part of the apparatus close to the position of the guides 8 in the compacting position. Figures 4 and 5 schematically show two different possible positions of the auxiliary guide columns 9 and the corresponding guides 8 in the pull yoke 6, whereas the positions of the guides 7 for the guide columns 5 are the same in the two Figures. Figures 6, 7 and 8 show alternative constructions for providing a direct guiding of the pull yoke 6 in the compacting position. The construction shown in Figure 6 comprises rollers 14 connected to the pull yoke 6 and engaging corresponding rolling surfaces 15 on a fixed part of the apparatus. Naturally, the positions of the rollers 14 and rolling surfaces 15 may be reversed. The construction shown in Figure 7 comprises bearing surfaces 16 on the pull yoke 6, co-operating with corresponding bearing surfaces 17 on a fixed part of the apparatus. Due to the fact that the direct guiding of the pull yoke 6 is only needed in the compacting position thereof, the bearing surfaces 17 may be formed in such a way that they are only in contact with the bearing surfaces 16 on the pull yoke 6 in positions close to this compacting position, whereby a "docking" function for the pull yoke 6 is provided. The construction shown in Figure 8 comprises continuations of the columns 5 behind the pull yoke 6 and, at least during the compacting, these continuations of the columns 5 are engaging guides 18 connected to a fixed part of the apparatus. It will be evident for a man skilled in the art that many other alternatives may be envisaged without departing from the following claims.

Claims: CLAIMS 1. Apparatus for producing casting mould parts by compacting sand or other like material between a vertical squeeze plate (1 ) and a vertical swingable plate (2) forming movable end walls in a squeeze chamber (3), wherein the swingable plate (2) swings away after compaction to allow passage of the mould part from the squeeze chamber (3) by further forward movement of the squeeze plate (10), and the swingable plate (2) is journalled on a front yoke (4) which is in turn mounted on guide columns (5) for movement relative to said squeeze chamber (3), a pull yoke (6) is placed behind the squeeze chamber (3) and connected to the guide columns (5), the front yoke (4), the pull yoke (6) and the guide columns (5) thus forming a rigid frame structure parallel with the longitudinal axis of the squeeze chamber (3), at least two guide columns (5) being journalled in a corresponding number of guides (7) connected to the squeeze chamber (3) or other fixed part of the apparatus close to the position of the front yoke (4) in the compacting position, c h a r a c t e r i z e d by comprising guiding means (8,9,14,15,16,17,18) for guiding the pull yoke (6) against movements in a plane perpendicular to the intended movement of the pull yoke (6), said guiding means (8,9,14,15,16,17,18) directly guiding the pull yoke (6) and being connected to a fixed part of the apparatus close to the compacting position of the pull yoke (6). 2. Apparatus in accordance with claim 1 , c h a r a c t e r i z e d by the guidance of the pull yoke (6) being provided by means of at least one guide (8) journalled on a corresponding number of auxiliary guide columns (9), said auxiliary guide columns being connected to the squeeze chamber (3) or other fixed parts of the apparatus close to the backside of the squeeze chamber (3) at one end and to a fixed part of the apparatus close to the compacting position of the pull yoke (6) at the opposite end. 3. Apparatus in accordance with any of the preceding claims, c h a r a c t e ri z e d by comprising two auxiliary guide columns (9) positioned to engage guides (8) located symmetrically in the pull yoke (6). 4. Apparatus in accordance with claim 1 , characterized by the guidance of the pull yoke (6) being provided by means of rollers (14) and roller surfaces (15) provided on the pull yoke (6) and a fixed part of the apparatus, respectively. 5. Apparatus in accordance with claim 1 , characterized by the guidance of the pull yoke (6) being provided by means of co-operating bearing surfaces (16,17) provided on the pull yoke (6) and fixed parts of the apparatus, respectively. 6. Apparatus in accordance with claim 1 , characterized by the guidance of the pull yoke (6) being provided by means of continuations of the guide columns (5) behind the pull yoke (6), co-operating with corresponding guides (18) mounted on fixed parts of the apparatus. 7. Apparatus in accordance with any of the preceding claims, ch a ra cte r- i z e d by the frame structure comprising four guide columns (5) connecting the yokes (4,6) at their corners. 8. Apparatus in accordance with claim 7, characterized by all four guide columns (5) being journalled in guides (7) connected to the squeeze chamber (3) or other fixed parts of the apparatus close to the front end of the squeeze chamber (3). 9. Apparatus in accordance with any of the preceding claims, ch a ra cte ri z e d by the movements of the squeeze plate (1), and the frame structure consisting of the yokes (4,6), the guide columns (5), etc., respectively, are provided by means of respective hydraulic drive units (10,11).

Inventors: JOHANSEN JAN BECHMANN, JOHANSEN, JAN, BECHMANN
Applicants: GEORG FISCHER DISA AS, JOHANSEN JAN BECHMANN, GEORG FISCHER DISA A/S, JOHANSEN, JAN, BECHMANN
Application year: 2000
Main classification: B22C11
IPC codes: B22C11, B22C15, B22C21