MXPA96002232A

MXPA96002232A - Press plate uniformly comprimi

Info

Publication number: MXPA96002232A
Application number: MXPA/A/1996/002232A
Authority: MX
Inventors: Glaesener Pierre
Original assignee: Husky Injection Molding Systems Ltd
Priority date: 1995-06-07
Filing date: 1996-06-06
Publication date: 1998-04-01

Abstract

The present invention relates to press platen for use in a clamping operation wherein a force is generated in a first direction, comprising: press mold plate having two walls spaced apart from each other, with a first wall being the side of the mold and a second wall which is spaced from and parallel to the first wall, wherein the first and second walls extend substantially transverse to the first direction of the force, wherein each of the first and second walls has edges and a central area and wherein an intermediate support structure is positioned between and connects both walls, characterized in that the intermediate support structure is adapted to direct the force in the opposite direction from the edges of the first wall to the central area of the first wall for substantially Prevent deflection of the first wall and have a narrow end and a wide end and have an arched, conical shape, and n "V" or "

Description

UNIFORMLY COMPRESSABLE PRESS PLATE BACKGROUND OF THE INVENTION The present invention is directed to press plates used with machines and molding presses and more particularly, with a press plate having a design which allows deflection of the minimum plate at a minimum plate weight. Injection-molded press plates are typically in the form of a pad as shown in U.S. Patent No. 5,188,850 to Hirata et al .; U.S. Patent No. 5,066,217 to Fukuza a, et al .; U.S. Patent No. 5,110,283 to Blüml et al .; U.S. Patent No. 5,162,782 to Yoshioka; and U.S. Patent No. 5,192,557 to Hirata et al. In each of these patents, the molded press platen is substantially block formed having a substantially rectangular side, which supports one half of the mold. During the clamping of the mold halves, a force is generated against the mold mounting surface of the press platen. As is typical with such block shaped press plates, the mounting surface of the mold is caused to deform concavely, forcing the upper and lower edges of the sides towards the incoming force and causing the press plate to flex and provide pressure through the back side of the mold press plate. As a result, under the clamping force upwards, the center of the press platens are separated causing a space between the mold halves and in some cases, the burr formation is a by-product. U.S. Patent No. 4,615,857 to Baird discloses an encapsulation means and method for reducing flash formation during molding operations. According to this device, it is intended that the injection and transfer molding of the plastic be made in a form "that virtually eliminates burr formation. The deflection of the mold press in it, is measured with the mold press in the fastened configuration. The support structure of the mold is arranged to apply a force equal to the surface of the mold, forming support posts and bars, in such a way that they act as individual springs against the surface of the mold and in response to the generated force, while the mold is in the fastening configuration. The spring constants and lengths of the posts and support bars are calculated taking into account the actual deflection found in the mold press and therefore produce a uniform pressure on the molds during the clamping of the press.

Accordingly, the flexure of the mold press plates during the sealing of the mold is measured and the compressibility of the mold mounting blocks of the device, are adjusted as a function of the lateral position on one or both press plates to compensate the bending of the press plate, in such a way that a constant force is applied to the dividing surface of the mold, independent of the lateral position on the dividing surface. The stiffness and length of the mounting blocks define the force provided by the mounting blocks and are determined according to the predetermined formulas, depending on the position of the block on the press platen and the deflection of the predetermined press platen. Although Baird compensates deflection, the method and apparatus by which this is achieved, it is very complex requiring individual designs for particular forces to be generated with particular molds. Therefore, a uniformly applicable design is not achieved. FIGURES la and Ib disclose a molding press plate of the prior art, which has a slightly different shape than the block-shaped press plates discussed above, in the cited patents. As shown in Figure la, the mold press plate has a profile including several openings through it, a front wall and a back wall. As shown in FIGURE Ib, a plurality of grooves and flanges extend towards the rear wall, which can and has a surface area smaller than the front wall of the plate. The press plate also includes holes in each corner thereof to receive the tension bars that resist the force F between the press plates during the clamping of the mold. Each tie rod carries a resistance force FR, as shown. The plurality of ridges and grooves are provided to decrease the weight of the press plate. That is, the mounting surface of the front mold is under compression during the upper clamping of the mold, while the back wall is under tension as in a simple beam. The tie rods are pulled inward and deformed to conform to the movement of the surface of the press platen, as it moves along the dotted line and the arrows in Figure 1, thereby causing the mold surface to flex and having a concave configuration during molding, similar to the press plates of the patents mentioned in the above. Accordingly, despite the design of the molded press plate of FIGURES la and Ib, the flexure of the mold surface is not compensated for, and the possibility of burr creation is still existent. Since both sides of the curved plate, the supports of the corners of the connecting rods are also flexed resulting in a non-uniform load of the supports of the connecting rod. This causes the bending of the tie rods and high concentrations of tension that lead to failure due to premature fatigue. The arrows C show how the connecting rods flex during the hold up. Therefore, there is a need for a simple design and a lightweight press platen, which includes a means for compensating the deflection of the platen for press during molding or clamping pressure and which substantially eliminates burr creation.

BRIEF DESCRIPTION OF THE INVENTION The main purpose of this invention is to provide a molded press platen for use with molding or clamping applications, which results in substantially flat and parallel molding mounting surfaces during top clamping. Another object of this invention is to provide a molded press platen for use in injection molding applications as in the foregoing, which is lightweight. Still another object of this invention is to provide a molded press plate, designed to direct the clamping force during upward clamping of the connecting rods at the edges of the press platen, towards the mounting area of the central mold of the press. press plate, eliminating any curvature of the press plate. Yet another object of this invention is to provide a press plate for molding mold mounting, which remains almost completely flat during upward clamping and substantially prevents "burr" formation, and yet another object of this invention is that of providing a mold press plate having two sides and an intermediate support structure, which prevents the mold press plate from deflecting unevenly on the molding side during upward clamping. of this invention is to provide a mold press plate having two walls and an intermediate arch support structure, central, between the two walls, which substantially prevents uneven deflection of the plate on the molding side And yet another object of this invention, is to provide a press plate for molding that has two sides and a support structure in conical, intermediate, for substantially avoid deflection of the non-uniform press plate on the molding side. Another object of the present invention is to provide a molding chuck for eliminating the uneven load of the tie rods and nuts during upward clamping. The above objects are achieved by the molding press platen of the present invention, for use in a clamping operation in which a force is generated having a first direction. The press plate includes a first wall having edges and a central area and at least first and second sides, wherein the first side is adapted to be placed closer to the holding operation. The press plate further includes a second wall separated and substantially parallel to the first wall, in which the first and second walls extend substantially transverse to the first direction of the force. The means for directing the force from the edges of the second wall towards the central area of the first wall, are provided to substantially avoid non-uniform deflection of the first wall along the first side. The purpose of the second wall is to resist the separation forces created by the intermediate structure.

The details of the present invention are set forth in the following description and drawings in which like reference numerals represent similar elements.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a side elevational view of a press plate for molding of the prior art and the forces and deflections, which are carried out during an upward grip using this press plate for molding; FIGURE Ib is a front elevation view of the molding press plate of the prior art, shown in FIGURE la; FIGURE 2 is a sectional view in elevation of the plates of FIGURES 3 and 5 according to the principles of the present invention; FIGURE 3 is a perspective view of the press platen of FIGURE 2; FIGURE 4 is a sectional elevation view of another embodiment of a press platen in accordance with the principles of the present invention; and FIGURE 5 is a perspective view of another embodiment of a press platen in accordance with the principles of the present invention, also represented by the sectional view of FIGURE 2.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY Now with reference to the drawings in detail, there is shown in FIGURE 2, an elevation and cross-sectional view of a first embodiment of the press platen of the present invention, for use in a molding application and in FIG. 3 a perspective view of the press platen shown in FIGURE 2, generally designated as 10. In general, the platen 10 for press includes a molding assembly wall 12 adapted to retain the half 17 of a mold and the end wall 14 and the intermediate structure 16 placed between the molding wall 12 and the final wall 14. FIGURES 4 and 5 represent additional embodiments of the press platen of the present invention and from a general standpoint, the embodiments of FIGURES 2, 4 and 5 are similar. FIGURE 4 represents the particularly preferred embodiment, ie, one with an inclination in place of arched walls or one having an intermediate conical portion, as shown in FIGURE 5. The above description and the following description, unless if it is indicated in another form, it applies equally to all modalities and with respect to the figures, equal numbers designate equal elements. The mold mounting wall 12 is adapted to maintain a mold half 17 for use in engagement with another mold half (not shown) to create a mold and to sufficiently secure the other half of the mold by means of fastening forces F shown by the arrows. The reaction forces FR on the connecting rods 25 are further represented by the arrows. The mounting wall 12 of the mold is substantially rectangular in shape, although other shapes may be used, extends substantially transverse to the force F, and preferably, in one of the two plates in a machine, includes an opening 18 through the center thereof for the insertion of an injection unit 20. As shown in the cross-sectional view of FIGURE 2, the tip 22 of the injection unit 20 preferably extends through the opening 18 to connect with the mold half 17 thereby contributing to the use of the efficient space. The mold mounting wall 12 also includes a hole 24 that is substantially larger in diameter than the tie rod 25 at each corner thereof to receive the tie rods 25. The mounting wall 12 of the mold is adapted to receive four connecting rods 25, which extend through it and towards the end wall 14. The intermediate support structure 16 provides a mechanism by means of which the mold mounting wall 12 of the plate 10 is prevented from non-uniform bending during the application of the clamping force F and as a result of such non-uniform bending, it avoids burrs and wear on the components of the molding machine. The intermediate support structure 16 includes one or more internal flanges 26 and / or 28 extending from the inner side 27 of the mold mounting wall 12 to the inner side 29 of the end wall 14, causing the support structure intermediate has a narrow end and a wide end. For the embodiment of FIGURE 5, the intermediate support structure is preferably a continuous wall in a semi-spherical or conical shape, which is attached to the end wall and the mold mounting wall, similar to what is described in the following with respect to the upper and lower flanges. The flanges 26 and 28 are attached to, and extend substantially outwardly from a central area 30 of the inner side 27 of the mold mounting wall 12, forming a narrow end, to the outer edges 32 and 34, respectively, of the side 29 inside the end wall 14, forming a wide end and the cavity 31 between the flanges 26 and 28. Accordingly, the central area 30 is located opposite the intended mold mounting area of the mold mounting wall 12. The flanges 26 and 28, therefore, support the surface of the press plate directly where the mold is located. Accordingly, in one embodiment, a singular upper flange 26 extends from the central area 30 of the mold mounting wall 12 and is joined with, an upper edge 32 of the inner side 29 of the end wall 14. Preferably, the upper flange 26 is attached to, and extends through the entire width of the inner side 27 of the molding wall 12 as shown in the perspective view of FIGURE 3, although this design may be biased as it is discussed in the following. Similarly, the lower flange 28 is also attached to, and extends from the central area 30, preferably along the entire width of the inner side 27 of the mold mounting wall 12 and is attached to the edge 34 below the inner side 29 of the wall 14. Although the flanges 26 and 28 have been described as substantially contiguous and extending across the full width, the present invention also contemplates the flanges 26 and 28 which are formed of a plurality of flanges separated which have smaller widths and are separated from each other and do not necessarily cover the entire width of the mold mounting wall and the end walls.

With particular reference to the. FIGURE 2 and the embodiment shown therein, the resulting structure formed by the upper flange 26 and the lower flange 28 is substantially an arc or C-shaped, in which each flange is arched outwardly relative to the cavity 31 of the plate 10 for the press. With particular reference to FIGURE 4 and the embodiment shown therein, the upper flange 126 and the lower flange 128 are substantially straight, extending from the central area 130 to the upper edge 132 and the lower edge 134, respectively, of the wall 114. of end. In this embodiment, the resulting shape is substantially V-shaped. The cross section taken horizontally, could be substantially the same to define another embodiment, ie, such as the conical version shown in FIGURE 5. As representative of the cross section of the embodiment of FIGURE 5, FIGURE 4, could not include the holes 124 and the portion of the connecting rods 125 observed in the cavity 131, could not be observed, since the wall 226 would block the view. With particular reference to FIGURE 5, and the embodiment shown therein, the intermediate support structure 216 comprises a wall 226, which is conical or spherical in shape with the narrow portion of the conical or spherical shape attached to the surface 227. interior of the wall.212 of the mold assembly and the wide portion of the conical or spherical shape attached to the inner surface 229 of the end plate 214. The conical or spherical wall can be divided into sections for ease of fabrication or it can be a singular cast part. Due to the conical or spherical shape, the wall 226 of the intermediate 216 would normally not be able to extend across the entire width of the end walls and mold assembly as described above for the embodiments of FIGS. 2 and 4 The embodiments in FIGS. 2, 4 and 5, the upper and lower flanges of the intermediate support structure or wall of the conical or spherical support structure are joined to the molding wall 12, 112 or 212, respectively. at an acute angle OJ with respect to them (not shown in FIGURE 5, but similar to FIGURE 4), and to the end wall 14, 114, or 214, respectively, at an acute angle to it (not shown) in FIGURE 5, but similar to FIGURE 4). The end wall 14 is also preferably rectangular in shape, although other shapes may be used, and extends substantially parallel to the wall 12, the transverse force F, and may include an opening 36 therethrough, in which the injection unit 20 can be adapted to extend to inject the melt into the mold half 17. Similar to the molding wall 12, the end wall 14 includes the holes 38 in alignment with the holes 24, one at each corner thereof, to receive the connecting rods therethrough. Each of the holes 38 may include, if necessary, a countersink 40 to receive the nuts 42 of the. connecting rod. The upper flange 26 and the lower flange 28 may also include the openings 48 and 50, respectively, therein and in alignment with the holes 24 and 38 of the walls 12 and 14 to receive the connecting rods 25, as required. The end wall 14 may further include purge openings 44 therein, adjacent the flanges 26 and 28, through which the melt escapes, purges and / or burrs may exit the platen running downwardly from the interior surface 46 of the interior. lower flange 28 and through the purge opening 44. Although the press plates as shown, are formed of a cast material, it is also feasible that the elements thereof, ie, the walls and intermediate support structure can be formed separately and fastened together in any form, which will provide the force necessary to withstand the forces developed during upward clamping. During the operation, the plate 10 can be used, for example, with movable and stationary plates used in the molding machines and mechanical presses or other clamping mechanisms, in which the deflection of a plate is possible due to the clamping forces ^ upwards generated and in singular and serial designs of these molding machines and presses and other fastening mechanisms. During upward clamping, although the plate 10 is used, the intermediate support structure 16 and the arrangement of the relative mold mounting wall 12 of the intermediate support structure 16 is such that the clamping forces F at the edges of The plates are directed towards the center of the plate where half of the mold is located, that is to say, operating at the beginning of a bridge to provide support directly under the mold. Accordingly, the mold mounting surface of the plate is deformed into a substantially parallel shape, thereby substantially preventing bending or bending and burr creation. The force F which develops in the mounting surface of the mold of the plate 10, during the clamping is indicated by the large arrow in FIGURE 2. The force F acting on the plate during the clamping of the mold is dissipated outwards as the outside F, as indicated by the small arrows, along the inner flanges 26 and 28 causing the intermediate support structure 16 to be in compression as indicated by the arrows C and causing the mold surface of the wall 12 is in a neutral state in terms of bending forces acting on them in opposite ways. Further, the end wall 14 is caused to be in tension as indicated by the arrows T, although the connecting rods each with the reaction force FR are pushed slightly outwards due to the stretching of the end wall 14. As a result of this action of forces on and within the plate, the mounting surface of the mold of the mold wall 12 is not uniformly deflected. The force distribution described in the foregoing is applicable in the same way to each of the embodiments covered herein, that is, the intermediate support structure in the form of an arc or C, and the intermediate support structure in the form of a V shown in FIGURES 2 and 4, respectively, and also the intermediate support structure in conical or spherical form shown in FIGURE 5. The main advantage of this invention is that a plate is provided for use with molding or clamping or pressing applications. , or which results in substantially flat and parallel mold mounting surfaces during vertical or upward clamping. Another object of this invention is that a plate is provided for use in injection molding applications, which are lightweight. Still another object of this invention is that a plate is provided, which is designed to direct the clamping force during the upward clamping of the connecting rods, at the flanges of the plate towards the mounting area of the central mold of the plate, eliminating any curvature of the plate. Yet another object of this invention is that a plate is provided having a mold mounting surface, which remains almost completely silver during upward clamping and substantially prevents flash formation. And yet another object of this invention, is that a plate is provided, having two walls and an intermediate support structure, in the form of a central arc between the two walls, which substantially avoids uneven plate deflections from the mounting side of molding it. And yet another object of this invention is that a plate having two walls and a support structure in a conical or spherical shape, intermediate therebetween is provided to substantially avoid deflection of the non-uniform plate on the molding side. Another object of the present invention is to provide a platen for molding press to eliminate unequal loading of the connecting rods and nuts during upward clamping. Since the deflection of the plate is minimized, the loading of the connecting rods is substantially uniform and any bending of the resulting connecting rod is substantially eliminated.

It is to be understood that the invention is not limited to the illustrations described and shown herein, which are considered to be only illustrative of the best modes of carrying out the invention and which are capable of modification of the shape, size, arrangements of the parts and operation details. On the contrary, the invention is intended to encompass all such modifications, which are within its spirit and scope as defined by the claims. Having described the invention as above, property is claimed as contained in the following:

Claims

1. A press plate for use in a holding operation, in which the force is generated having a first direction, characterized in that it comprises: a first wall having edges and a central area and at least first and second sides, in which the first side is adapted to be placed closer to the fastening operation; a second wall separated from, and substantially parallel to, the first wall, the first and second walls extend substantially transverse to the first direction of the force; and a means for directing the force of the edges of the first wall towards the central area of the first wall to substantially avoid non-uniform deflection of the first wall along the first side.

2. The press plate according to claim 1, characterized in that the means for the steering comprises an intermediate support structure placed between and joined to the first and second walls.

3. The confprmity press plate with claim 2, characterized in that the intermediate support structure is defined by a substantially V-shaped support wall, which defines a cavity between the first and second walls.

4. The press plate according to claim 2, characterized in that the intermediate support structure is defined by a substantially arch-shaped wall, which defines a cavity between the first and second walls.

5. The press platen according to claim 4, further characterized in that it includes a means for receiving an injection unit through the first and second walls and through the intermediate support structure.

6. The press plate according to claim 5, characterized in that the first and second walls have openings in them and lead to the cavity, in which the openings and the cavity are adapted to receive the injection unit.

7. The press plate according to claim 5, characterized in that the second wall includes a means for removing the burr from the cavity resulting from a molding operation, using the injection unit.

8. The press platen according to claim 7, characterized in that the means for elimination comprises an interior surface of the arc-shaped support wall leading to a purge hole through the second wall to allow the burr to escape of the cavity.

9. The press plate according to claim 2, further characterized in that it includes a means for being guided on the connecting rods.

10. The press plate according to claim 2, characterized in that the intermediate support structure is defined by a support wall having a substantially C-shaped cross section.

11. The press plate according to claim 2, further characterized in that it comprises the intermediate support structure defined by an arch-shaped support wall, having a narrow end and a wide end, in which the first wall is joined to the narrow end and the second wall is joined with the wide end.

12. The press plate according to claim 11, characterized in that the second side of the first wall is joined to the narrow end opposite the first side.

13. The press plate according to claim 2, characterized in that the first wall is adapted to support a first mold half for coupling with a second half of the mold to form a mold of a mold machine or by injection.

14. The press plate according to claim 2, characterized in that the intermediate support structure comprises a plurality of flanges joined to, and between the first and second walls and oriented at acute angles with respect to the first and second walls.

15. The press plate according to claim 14, characterized in that the plate has a width and the plurality of flanges includes an upper flange and a lower flange extending across the width of the press platen.

16. The press plate according to claim 15, characterized in that the second side of the first wall has a central area and the second wall includes upper and lower edges, wherein the upper flange extends from the central area to the upper edge and the lower flange extends from the central area to the lower edge.

17. The press plate according to claim 16, characterized in that the upper and lower flanges form an intermediate support structure in the form of an arc.

18. The press plate according to claim 16, characterized in that the upper and lower flanges form an intermediate support structure in the form of an arc.

19. The press plate according to claim 2, characterized in that the intermediate support structure is defined by a conical wall. 2b

20. The press plate according to claim 1, characterized in that the means for steering further prevents the first side of the first wall from being deflected in a second direction transverse to the first direction.