HU203295B - PROCEDURE FOR THE MANUFACTURE OF A SYMBOL SEMETIC SURFACE SURFACE FLOOR PLATE FOR DISCARDING THE PROCEDURE - Google Patents

Abstract

Method for producing a shape with a rotationally symmetrical concave surface from a flat plate, during which the plate is pressed against the edge (3) of a shaped body (1) having a concave recess corresponding to the desired surface, and then the plate (4) is pressed axially from the side opposite to the recess of the shaped body (1) with a stamp shaped in the shape corresponding to the said concave recess, where a stamp with several stamp arms (9) is used, the profile of the stamp arms (9) has a smaller curvature than the recess of the shaped body (1), and the shaped body (1) and the stamps with several stamp arms (9) are rotated relative to each other during the axial displacement. The device suitable for implementing the method comprises a shaped body (1) with a rotationally symmetrical recess, a wrinkle-holding ring (5) for clamping the sheet (4) to be placed thereon, and a stamp consisting of several radially arranged stamp arms (9), the profile of which matches the profile of the recess of the shaped body (1), but has a smaller curvature in its central region. (Figure 1)

Description

The present invention relates to a process for producing a rotationally symmetrical concave surface from a flat plate and to an apparatus for performing the process.

Various methods of producing rotationally symmetrical concave surfaces, such as mirrors for parabolic antennas, and reflectors are known.

In one known method, the initially selected sheet is blasted in liquid into an mold of the desired shape, the compression force being exerted by the shock wave produced by the blast. The productivity of this process is low, requiring special facilities and equipment, only larger in size and economical for single or small series products.

High roll accuracy is achieved by the roller process, in which the properly gripped plate is rolled from the outside, i.e. from the convex side, to a stamp with a surface formed corresponding to the concave side. By removing the deformation roller radially from the center, it is pressed against the plate with a given force, while the roller deforms the plate and "irones" it on the inner shape. The surface of the roller not only rolls on the surface of the plate but also slides laterally. In this process, the tool for rotating and controlling the roller is very expensive, the roller is heavily loaded, worn, and the forming takes a long time.

In another known method, the flange of the flat plate is clamped and pressed between a concave shape formed according to the desired rotation surface and a convex stamp formed in the same way. Such a process is described, for example, in SE 451 365. Extrusion is one of the most widely used sheet processing methods, allowing for productive production.

However, it has been found that this method is not suitable for the production of precisely shaped shapes. The vast majority of the parabolic mirrors used today are not made with conventional stamping because they do not maintain the geometric accuracy required for the mirror.

When analyzing the accuracy errors, we find that sections of the surface thus extruded show signs of increased tensile strength and others, and that the shape produced alternates from the theoretical to the positive and negative directions.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for retaining the advantages of extrusion while allowing high dimensional accuracy and adequate surface quality.

In order to solve this problem, we have come to realize that we have analyzed more closely the deformation of the plate wedged between the tools precisely shaped to the desired shape. When the stamp is penetrated, the center portion is first convex, corresponding to the final curve, and when the stamp is pressed more in the axial direction, the deformation of the lateral surfaces tends to exert a curvature on the center. This tension interferes with the convex center portion and is exerted by a plate force on the lateral portion of the disc extending laterally from the central convexity, as this disc section is rigidly gripped by the annular portion of the stamp. As a result of the force exemplified herein, the plate is crumpled and then tends to smooth through further deformation. When the two tools reach their final position, the plate has very high voltages, and after opening the tool halves, the plate remembers deformation and an "S" shaped error occurs.

According to the invention, this defect must be assisted by preventing the sheet from creasing during deformation. If the convex stamp on one side of the disc has a smaller curvature (convexity) associated with the other side of the disc and defining the final profile, then there is an optimum shape in which the force is "self-" caused by deformation of the outermost section during machining. presses into a shape and takes its shape, while the middle section is no longer in contact with the stamp.

The present invention provides a method of forming a rotary symmetrical concave surface from a flat plate by clamping the plate to a flange of a concave recess having a concave recess corresponding to the desired surface, and a stamp having multiple stamp arms is used, wherein the profile of the stamp arms is less curved than the recess of the mold, and the mold and the stamp having multiple stamp arms are rotated relative to each other during axial displacement.

In a preferred embodiment of the method, the rotated parts are centered relative to one another.

The apparatus for carrying out the process comprises a body having a rotationally symmetrical recess, a chain-clamping ring holding the plate to be inserted thereon, and a stamp consisting of a plurality of radially arranged stamp arms having a profile curved but less in the center region.

In a preferred embodiment, the stamp arms are provided with press inserts defining the active surface of the stamp.

In another preferred embodiment, the stamp arms are formed by rollers mounted on an axis and guided to rotate thereon to form said profile.

From the structural point of view, it is advantageous for the stamp arms to engage with the stamp body.

For centering purposes, it is expedient to have a bushing leading to the molded body having rollers for centering the stamp body.

It is advantageous for the molded body and optionally the stamp arms to be formed from a plurality of concentric interconnected parts for the production of fittings of various sizes.

The present invention enables the production of moldings of very precise size with good shape, low process power requirements and favorable productivity. Good shape fidelity gives a shiny, scratch-free surface.

The present invention will now be described

-2EN 203295Β In an exemplary embodiment, the drawings are described in more detail. The drawing shows:

Figure 1 is a schematic diagram of the apparatus of the invention, a

Figure 2 is a profile diagram of the body and the stamp, a

Figure 3 is a sectional view of a roller stamp arm and a

Figure 4 is a sectional view of a multipart molded body.

The tool arrangement outlined in Fig. 1 consists of two main parts, the first part of which is a mold 1 with a concave inner surface corresponding to the shape of the rotating surface to be manufactured, hereinafter for the sake of simplicity. The molded body 1 has central holes 2 and 3 flanges. The plate 4 to be machined rests on a planar flange 3 of the molded body 1 and the clamping ring 5 is applied to hold the clamping force required for positioning. The wrist ring 5 is surrounded from the outside by a guide sleeve 6 and the clamping force is transmitted by the shoulder of the guide sleeve 6. Several centering rollers 7 project from the cylindrical inner surface of the guide bushing 6. During machining, the guide bushing 6 is pressed against the mold body 1 by means of a clamping connection (not shown) and the flange 4 is fixed with this force.

The tool has an axially guided movable part of the mold body 1 which holds the stamp arms 9 mounted on the stamp body 8. The stamp arms 9 are radially evenly spaced from one another, their outer surface having a convex curved shape, the curvature of this surface being less than the concave surface of the molded body 1 in accordance with the principle of the invention. In the exemplary case, the number of stamp arms 9 is four, only one of which is shown in Figure 1. The number of stamp arms 9 may be selected depending on the thickness of the plate 4, the degree of deformation, and the size of the rotary body to be formed, but preferably between 3 and 10 arms. Between the stamp body 8 and the stamp arms 9, I have a circular symmetrical insert 8a made of plastic and the stamp arms 9 rest on it. A guide shaft 10 is connected to the stamp body 8, which passes through the central bore of the plate 4, the bore 2 of the mold body 1, and is guided beyond the mold body 1 by a guide hole formed in a sketch 11 shown schematically. The actual printing surface is formed from textile bacilli 12, polyamide or other similar material made of a sufficiently tough elastic material, which is attached to the stamp arms 9. Alternatively, printing presses 12 which are substantially harder than the plate 4 (eg hardened steel) may be used.

The moving part is connected to a rotary and feed mechanism not shown in the drawing.

During machining, the moving part is moved towards the mold body 1 during rotation. Centralized guiding is provided by guiding axle 10. When machining larger diameter sections, the outer guide sleeve of the stamp body 8 is kept centered by the centering rollers 7 of the guide sleeve 6 during machining, thereby reducing the stress on the guide shaft 10 and the risk of bending. The press inserts 12 of the stamp arms 9 first contact the central portion of the plate 4 and, under the action of the feed force for feeding, the plate 4 takes the shape of a rotation surface defined by the press arms 12. As the feed continues to be picked up, the radial extension of the deformed surface increases.

The solid line 13 in Figure 2 gives a profile curve of the concave surface of the mold 1. If the thickness of the plate 4 is taken into account, the line 14 represents the profile of the rotation surface defined by the presses 12, in particular in a situation where the presses 12 have entered the mold body 1 and no further feed is possible due to the thickness of the plate. The collision occurs in the extreme ranges, where the distance between the lines 13 and 14 corresponds exactly to the thickness of the plate 4. The dashed line 15 denotes an arc drawn at exactly the same thickness as the sheet 13. The curvature of the line 14 is smaller, so that a deviation is observed with respect to the theoretical fit line 15, the degree of which increases towards the center. The maximum deviation d is indicated in Figure 2. The extent of the undercut depends on the material of the plate 4 and the ratio of rotation surface F / D (focus / diameter) can be determined empirically. Typical value for Al is 99.5 with a F / D ratio of 0.38 for a 1mm thick sheet and 3mm for a D / 1.5m and 5mm for a 2.5mm sheet thickness.

As the outer sections of the sheet 4 are pressed, the middle section of the sheet 4 continues to move toward the molded body 1 and is tensioned against its concave surface. By undercutting the printing surface, the alternating forces (tensile and compression forces) of the plate 4 are not affected by the alternating forces (tensile and compression forces) on the inner and middle regions of the plate 4, Thus, once the force has ceased, the disk 4 maintains the recorded shape exactly.

A further feature of the process according to the invention is that it produces a very high quality surface, out of the shape defining surfaces the role of the molded body 1 is passive, the plate 4 is not inverted, whereas the multi-lever design is sufficiently flexible provide.

In order to eliminate possible problems due to sliding friction between the sheet surface and the stamp arm 9 and to reduce the machining power requirement, it is also possible to provide a roller design of the stamp arms 9.

Figure 3 illustrates the formation of a single stamp arm 9 from three interconnected rollers 17, 18, 19 arranged on a common axis 16, the profile of the rollers corresponding to the line 14 shown in Figure 2. The ends of the roller shaft 16 are properly secured to the stamp body 8. Of course, the number of rollers can be increased, it is essential that the rollers do not have axial play. This distance can be selected to be equal to or slightly greater than the radius of the axis 10.

The tooling costs can be significantly reduced if the mold body 1 is formed from a plurality of interconnected parts, as shown in Figure 4. The 1 design shown here consists of la, and down rings. If only the la ring is used, a parabola or other rotating surface with the same focal length but smaller diameter can be formed

-3GB 203295Β off, the surface can be enlarged using the second and third lb and down rings. Similarly, you can step up the stamp by using the rollers on the stamp arms in a specific assembly. The advantage of staggered design is that with a single press tool and a single stand, rotating surfaces of the required size can be created.

Although the arrangement is shown with a horizontal axis in the drawing, it can be seen that a vertical axis arrangement can be used in the same way, whereby the largest molded piece 1 can be fixed to the ground or even made of several reinforced concrete rings.

In the embodiment shown in the drawing, the molded body 1 and the plate 4 connected thereto formed the stator together, and the stamp body 8 with the stamp arms 9 and the press inserts 12 attached thereto formed the rotating moving part. It will be readily appreciated that the stationary and movable parts are interchangeable, and even the axial feed may be independent of rotation, so that one part may rotate at a fixed axial position and the other may move axially.

Claims (8)

PATENT CLAIMS A method of producing a rotationally symmetrical concave surface from a flat plate by clamping the plate to a flange of a molded recess having a concave recess corresponding to the desired surface, and axially pressing the plate with a stamp corresponding to said concave recess, A stamp (9) is used, wherein the profile of the stamp arms (9) has a less curvature than the recess of the mold body (1) and the stamp (1) and the stamp with the plurality of threaded lever arms (9) are rotated relative to one another. Method according to claim 1, characterized in that, during axial movement, the rotated parts are centered relative to one another. Apparatus for carrying out a method according to claim 1 or 2, comprising a mold body having a rotationally symmetrical recess, a wrinkle-clamping ring for clamping the plate to be applied thereto, and the stamp comprising a plurality of radially arranged stamp arms (9) it fits into the recess profile of the molded body (1) but has a smaller curvature in its central region. Apparatus according to claim 3, characterized in that the stamp arms (9) are provided with pressure inserts (12) defining the active surface of the stamp. Apparatus according to claim 3, characterized in that the stamp arms are formed by rollers (17,18, 19) mounted on a shaft (16) and guided in rotation therewith, forming said profile. 6. Apparatus according to any one of claims 1 to 3, characterized in that the stamp arms (9) are connected to the stamp body (8). Apparatus according to claim 6, characterized in that a bushing (6) is connected to the mold body (1), on which rollers (7) are centered on the stamp body (8). 8. Referring to FIGS. Apparatus according to any one of claims 1 to 4, characterized in that the molded body (1) and optionally the stamp arms (9) are formed from a plurality of concentrically connected parts.