METHOD OF CONSTRUCTING THE SWING-PLATE-BEARING SYSTEM IN A STRING-MOULDING MACHINE AND STRING-MOULDING MACHINE WITH SWING-PLATE-BEARING SYSTEM

Abstract: In a string-moulding machine of the kind comprising a swing plate (1) pivotally mounted on a front yoke (2) in order to be pivoted out of the way to provide a string-mould system, the front yoke (2) being mounted in a frame and guide system (6) for moving between a squeeze position and a delivery position, the swing plate (1), the front yoke (2), and the frame and guide system (6) are dimensioned in such a way that the forces acting on these elements during the squeezing operation induce the same angular deflection of the swing plate and front yoke, respectively, at the positions of the swing plate bearings, whereby simple sliding bearings may be used for the pivotal mounting of the swing plate (1) on the front yoke (2). Furthermore, this makes it possible to provide a simple adjustment possibility for adjusting the swing plate in the axial direction of the bearings.

Description: METHOD OF CONSTRUCTING THE SWING-PLATE-BEARING SYSTEM IN A STRING-MOULDING MACHINE AND STRING-MOULDING MACHINE WITH SWING-PLATE-BEARING SYSTEM TECHNICAL FIELD The present invention relates to a method of constructing the swing-plate-bearing system in a string-moulding machine and a string-moulding machine with a swing- plate-bearing system constructed in accordance with said method. BACKGROUND ART String-moulding machines of the kind, in which this invention is intended to be implemented, comprise a squeeze chamber for pressing moulds between a squeeze plate and a swing plate, each provided with a pattern. After pressing the mould, the swing plate is pivoted out of the way for bringing the mould out of the squeeze chamber and into abutment against a mould having been produced immediately before by moving the squeeze plate past the swing plate. For the moving towards and away from the squeeze chamber, the swing plate is pivotally mounted on a front yoke. The front yoke is in turn mounted in a frame and guide system for controlled movement. In order to accommodate deformation of swing plate, front yoke and frame and guide system during squeezing, the pivotal mounting of the swing plate on the front yoke has until now always been provided using spherical bearings. Due to the complexity of the mechanical system it has not been considered possible, nor necessary, to calculate the exact interdependent deformations of the different components. Furthermore, different systems have been made for adjusting the position of the swing plate in the direction of the pivot axis, such as adjustment screws pushing one side of one of the spherical bearings and a spring construction pressing on the opposite spherical bearing, the spring construction further producing an accommodation of different deformations of swing plate and front yoke in the direction of the pivot axis. One problem with larger machines of this kind is that the larger pressure forces require larger bearings for the swing plate. In machines of this kind, the return movement of the swing plate from the out-of-the-way position to the squeeze position is normally provided by gravity and with larger bearings the friction forces may rise to a level, where this is not practicable. In order to reduce the friction forces in the bearings it has been suggested to use spherical roller bearings instead of spherical sliding bearings, but such bearings require more space than the sliding bearings in order to withstand the same forces, and roller bearings are not well-suited for static forces, i.e. forces applied when the rollers are stationary. Another problem with spherical bearings is that they require a cumbersome adjustment procedure during installation. DISCLOSURE OF THE INVENTION Based on this prior art it is the object of the present invention to provide a method of constructing the swing-plate-bearing system in a string-moulding machine and a moulding machine with swing-plate-bearing system constructed in accordance with said method, with which it is possible to use simple sliding bearings for the pivotal mounting of the swing plate and thereby avoid the above problems of the known spherical bearings and this object is achieved by the method in accordance with claim 1 and the string-moulding machine in accordance with claim 6. Preferred embodiments of the invention are revealed in the subordinate claims. BRIEF DESCRIPTIONS 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 a swing- plate-bearing system according to the invention shown in the drawings, in which Fig. 1 shows a sketch of a swing plate and a front yoke and the bearing system for the swing plate, Fig. 2 shows a sketch corresponding to Fig. 1, in which pressing forces have been applied, the movements of the different components being highly exaggerated for illustrative purposes, Fig. 3 shows a more detailed sketch of a bearing comprising components for adjusting the position of the swing plate in the direction of the pivot axis, and Fig. 4 shows a sketch of the bearing in Fig. 3 seen from the end. DESCRIPTION OF THE PREFERRED EMBODIMENT The swing-plate-bearing system shown in Figure 1 is constructed in accordance with the present invention and comprises a swing plate 1 pivotally mounted on a front yoke 2, said pivotal mounting being provided by means of bearing axles 3 mounted in the front yoke 2, and co-operating with bearing bushings 4 mounted in a bearing block connected to the swing plate 1. On the swing plate 1 a pattern 5 is mounted for providing the desired casting cavity in the mould produced in the string-moulding machine, in which the construction is implemented. The front yoke 2 is mounted for linear movement in the string-moulding machine by means of guide columns 6 guided in suitable guide bearings. In the squeeze position the swing plate 1 is partly supported on the front yoke 2 by means of the bearing construction 3, 4 at the upper part of the swing plate 1 , and partly by the pressure pads 15 at the lower part of the swing plate 1. During squeezing the different parts shown in Fig. 1 are subjected to deformation by the reaction force from the squeezed mould. These deformations are shown highly exaggerated in Fig. 2. As indicated in Fig. 2, the forces acting on the system during squeezing induces a bending of the swing plate 1 and the front yoke 2, resulting in an angular deflection of the bearing axles 3 and the bearing blocks with the bearing bushings 4. In accordance with the present invention the mechanical system is dimensioned in such a way that these angular deflections are mainly identical. In this way, it is possible to provide the bearings as simple sliding bearings in these positions, where normally spherical bearings have been used in order to accommodate different angular deflection of the front yoke 2 and the swing plate 1 at the positions of the bearings. The bearing construction shown in Fig. 3 provides a possibility of adjusting the position of the swing plate 1 in the direction of the pivot axis. The construction shown comprises a simple sliding bearing with a bearing axle 3 and a bearing bushing 4, the bearing axle 3 being mounted in a non-rotational but axially slidable manner in the front yoke 2. The swing plate 1 is fixed in the direction of the pivot axis relative to the bearing axle 3 by means of a connecting screw 8 positioned inside a distance tube 7 and a double row angular contact ball bearing 9 connecting one end of the connection screw 8 with the bearing axle 3. By means of this axial fixation, the bearing axle, bearing bushing and swing plate follow one another in the direction of the pivot axis when the bearing axle 3 is moved axially relative to the front yoke 2. This axial movement is controlled by means of an adjustment nut 10 in threaded engagement with the bearing axle and in planar contact with the side face of the front yoke 2, in combination with a number of fixation screws 14, which are loosened in order to be able to make an adjustment by means of the adjustment nut 10 and thereafter being tightened in order to move the bearing axle 3 and the adjustment nut 10 axially until the adjustment nut 10 is brought into planar engagement with the side face of the front yoke 2. As shown in Fig. 4 the adjustment nut 10 is provided with a pin 12 co-operating with an adjustment scale 11 mounted on the end surface of the bearing axle 3. Preferably the pin 12 co-operates with end stop means 13 on the adjustment scale in order to limit the adjustment possibilities. This is an advantage in order to reduce the risk of adjusting the position of the swing plate 1 to an extent, where the pattern 5 interferes with the sides of the squeeze chamber in the string-moulding machine. The bearing at the opposite side of the bearing construction shown in Fig. 3 may be constructed as a simple sliding bearing without any fixation means, whereby the adjustment movements of the swing plate 1 are accommodated by linear movement of the bearing bushing 4 relative to the bearing axle 3, and the bearing axle 3 may be fixedly connected to the front yoke 2. Preferably, the construction shown in Figure 3 is installed in such a way that the swing plate 1 is positioned centrally relative to the squeeze chamber by adjustment of the adjustment nut 10 and after this, the adjustment scale 11 is mounted and the pin 12 is bored into the adjustment nut 10 at the centre of the scale 11. In this way, the adjustment scale will indicate an adjustment relative to the central position of the swing plate 1. swing plate frame yoke bearing axle bearing bushing pattern guide columns distance tube screw double row angular contact ball bearing adjustment nut adjustment scale pin end stop for adjustment nut 10 fixation screws pressure pads

Claims: CLAIMS 1. Method of constructing the swing-plate-bearing system in a string-moulding machine of the kind comprising a swing plate (1) pivotally mounted on a front yoke (2) in order to be pivoted out of the way to provide a string-mould system, the front yoke (2) being mounted in a frame and guide system (6) for moving between a squeeze position and a delivery position, said method being characterised by comprising the following steps: A. Dimensioning the swing plate (1), the front yoke (2), and the frame and guide system (6) in such a way that the forces acting on these elements during the squeezing operation induce the same angular deflection of the swing plate and front yoke, respectively, at the positions of the swing plate bearings, and B. Using simple sliding bearings for the pivotal mounting of the swing plate (1) on the front yoke (2). 2. Method in accordance with claim 1, c h a r a c t e r i s e d by the dimensioning being performed using a computer simulation of the mechanical system. 3. Method in accordance with claim 2, c h a r a c t e r i s e d by the dimensioning being performed using a computer simulation according to the "finite element" method. 4. Method in accordance with any of the preceding claims, c h a ra ct e rised by further comprising C. Providing an adjustment possibility for adjusting the swing plate in the axial direction of the bearings. 5. Method in accordance with claim 4, characterised by the adjustment being provided by axially adjusting the position of the bearing elements at one side and the bearing elements at the opposite side following the adjustment movement by relative axial displacement of the sliding bearing components (3, 4). 6. Moulding machine comprising a swing plate (1) pivotally mounted on a front yoke (2) in order to be pivoted out of the way to provide a string-mould system, the front yoke (2) being mounted in a frame and guide system (6) for moving between a squeeze position and a delivery position, cha racte ri sed by the swing plate (1), the front yoke (2), and the frame and guide system (6) being dimensioned in such a way that the forces acting on these elements during the squeezing operation induce the same angular deflection of the swing plate (1) and the front yoke (2), respectively, at the positions of the swing plate bearings (3, 4) and the bearings (3, 4) pivotally mounting the swing plate (1) on the front yoke (2) being constructed as simple sliding bearings. 7. Moulding machine in accordance with claim 6, characterised by the swing plate (1) being connected to the front yoke (2) by means (7, 8, 9) providing a fixation of the swing plate (1) in the axial direction of the sliding bearing. 8. Moulding machine in accordance with claim 7, characterised by the axial position of the swing plate (1) being adjustable by adjusting the axial position of the fixation means (7, 8, 9). 9. Moulding machine in accordance with claim 7 or 8, characterised by the fixation in the axial direction being provided by means of a double row angular contact ball bearing (9) inserted between the front yoke (2) and the swing plate (1) and positioned centrally with respect to the sliding bearing at one side of the swing plate (1). 10. Moulding machine in accordance with claim 8 or 9, characterised by the axial adjustment being provided by means of an adjustment nut (10) and fixation screws (14), said adjustment nut (10) adjusting the axial position of the complete bearing construction (3, 47, 8, 9) relative to the front yoke (2). 11. Moulding machine in accordance with claim 10, characterised by the adjustment nut (10) co-operating with a scale (11) indicating the adjustment position. 12. Moulding machine in accordance with claim 11, characterised by the scale (11) comprising means (13) for limiting the adjustment range.

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: 1999
Main classification: B22C11
IPC codes: B22C11