RU2146180C1 - Method and apparatus for deforming articles of sheet material by rounding them - Google Patents

Abstract

FIELD: plastic metal working, possibly manufacture of three-dimension products of sheet blanks. SUBSTANCE: method comprises steps of feeding blanks of sheet material one after another in apparatus for imparting them round shape by plastically deforming them along circle arc by rounding until achieving desired constant radius. Portion of blank leaving rounding apparatus in position of rounding is deflected by means of guides while it is elastically deformed for shifting it to transporting position from rounding position and in the result above mentioned portion of elastically deformed blank is held under load. As soon as end portion of blank leaves rounding apparatus it jumps to transporting position by action of said load and sets free path for next blank of sheet material that also may be subjected to rounding deformation but only after previous rounded blank of sheet material is knocked out of said apparatus for further transportation. EFFECT: shortened time period of working, high quality of products. 18 cl, 11 dwg

Description

 The invention relates to a method and apparatus for folding products from sheet material.

 In accordance with the state of the art, rectangular or square flat pieces of sheet material are rolled up, for example to make shells of cans, and then both edges extending parallel to each other in the axial direction are welded, as a result of which pieces of sheet material are formed into a cylindrical shell.

 For coagulation, a piece of sheet material is converted into a curved shape in the apparatus for rounding due to the fact that, for example, with the help of a rounding wedge, it is guided to the inner rounding roller and immediately after that passes through the pressing position between the inner rounding roller and the outer rounding roller. As a result of this, the initially flat piece of sheet material is bent at a constant radius of rounding, so that the part of the piece of sheet material that leaves the pressing position does not move further in the initial feed direction, but enters in a natural folded position in an arcuate shape defined by the rounding radius. For the case when tin can shells are made, the curved sheet extends mainly along the entire circle of coagulation, so that the sheet material in the folded position appears as an almost closed cylindrical shell. In practice, a folding circle or a folded position can be easily deformed due to the weight and elasticity of the curved sheet material, which can be avoided by means of guides the rounded section of the sheet material of the means.

 The radius of the coagulation circle is determined by the radius of the inner rounding roll, the position of the rounding wedge and the elasticity of the sheet material (the thickness of the sheet material and the tensile yield strength). In the manufacture of can shells, it is usually installed in such a way that it is rather smaller than the radius of the finished welded shell, so that the folded sheet material is a cylindrical shell, and the axially extending edges slightly overlap each other.

 Typically, the guides of the rounded section of the sheet material of the tool consist mainly of a cylindrical inner circular mandrel and a generally hollow cylindrical outer guide, and the space between them defines a circular gap located in a circle of folding. After the final folding, a piece of sheet material is axially pushed out of the circular gap, and another piece of sheet material is introduced into the bending device and the circular gap.

 The cycle time required for coagulation of a piece of sheet material with the known method described above is composed of the time it takes to curl and the time it takes to push. Moreover, the clotting time is determined by the feed rate and the curl length of the sheet material. The ejection time is determined, inter alia, by the axial length of the rolled sheet product. In other words, this means that the blanks from the sheet material must be fed into the apparatus to give a rounded shape with minimal removal from each other, which does not depend on the folding process itself, but on the axial elongation of the rolled product from the sheet material and on the used ejector mechanism.

 The invention aims to reduce the coagulation cycle time. At the same time, the coagulation quality should not be reduced in any way, nor should much higher hardware costs be required for this, for example, taking into account the use of a faster ejection mechanism. This problem is solved using the method and device, which are defined in the relevant claims.

 Due to the fact that the rear end section of the finished rolled product from sheet material is moved to a different transportation position, there is room for the next sheet blank, the front zone of which is in the folding position, although the previous sheet blank has not yet left or has not completely left the apparatus to give a rounded shape. Accordingly, it is no longer necessary to wait for the next billet from the sheet material to be fed into the apparatus for rounding until it is released, which reduces the distance between the billets from the sheet material at a given feed, therefore, generally reduces the cycle time.

 In the device for implementing this method, means are provided for translating the back of the rolled product from sheet material into the transport position. This is possible due to the elastic deformation of the front part of the rolled sheet material by means of guide means, so that the back part of the sheet material in the process of folding is under load and, as soon as it is released by the pressing position, jumps to the transport position. It is also possible immediately after completion of the coagulation process to carry out a sharp braking in front so that the back zone, as a result of its inertia, is ejected from the coagulation position to the transport position.

The method and device in accordance with the invention are described using the following drawings, where:
FIG. 1a-c show a coagulation scheme in accordance with the invention in three successive phases;
FIG. 2 is a diagram of an apparatus for implementing the method in accordance with FIG. 1a-c in cross section;
FIG. 3 is a cross-sectional view of another embodiment of a device for implementing the method in accordance with the invention;
FIG. 4-9 is another variant of the method in accordance with the invention in six phases, implemented in the device in accordance with FIG. 3.

 In accordance with FIG. 1a, a blank 1 of sheet material is fed in the direction indicated by arrow Z to the pressing position P (indicated by a double arrow) in a round shape device. The device for rounding in FIG. 1a is not represented. Rounded shaped devices per se are known; an example of the implementation of such a device for giving a rounded shape, which is part of shown in FIG. 2 and 3 of the rounding apparatus 80 are described in more detail below using FIG. 3. In the device for rounding, the blank of sheet material 1, which is still flat, is plastically deformed in such a way that after leaving the pressing position P, it has the desired constant radius of curvature. The forward curved portion of the sheet material preform 1 thus enters, after exiting the pressing position P to the natural folded position, the corresponding coagulation circle is shown in FIG. 1a by a dash-dot line and indicated by A. Next to curl circle A in FIG. 1 and all other drawings, the dash line shows the eject circle B. The center B 'of the eject circle B is offset from the center A' of the coagulation circle A in the direction of arrow Z. The intersection points of both circles A and B are denoted by the symbols M and M '. The ejection circle B determines the transportation position of the finished rolled product 1 of sheet material; as soon as the sheet metal product 1 is in this transport position (as it happens, described below), it is also known in FIG. 1 of the ejector mechanism not shown in more detail, is pushed out of the apparatus to give a rounded shape in axial, i.e. perpendicular to the plane of the drawing, the direction and is transported further, for example to a welding device, which no longer touches the subject of the present invention.

 In FIG. 1a, a phase is shown in which the front part of a sheet material blank 1 has already passed the pressing position P and is plastically deformed to enter the folding position on the circle A.

 As shown in FIG. 1b, a sheet material blank 1 according to the invention is guided at the intersection point M 'from the coagulation circle A to the ejection circle B, which does not correspond to the coagulation circle described below using FIG. 2 way. The back zone of the sheet material blank 1 is still fixed by the pressing position P, which results in the fact that the section of the sheet material blank located between the pressing position P and the intersection point M 'is elastically deformed.

 FIG. 1c represents the position of the blank 1 of sheet material shortly after the completion of the folding process. As a result of elastic deformation of the front portion of the sheet material blank, which is located on the ejection circle B, the rear portion of the sheet metal blank, since it is no longer held by the pressing position P in the area of the rolling circle A, also freed up in the area of the ejection circle B, so that the entire blank of sheet material is on the ejection circle B, i.e. in transport position. Now the blank 1 of the sheet material can be pushed out of the apparatus to give a rounded shape in the axial direction. At the same time, the next workpiece 2 is already in the folding process, and its front zone passes along the folding circle A to the folding position, which is timely released, since now the back of the blank 1 from sheet material is on the pushing circle B. The blank 1 from the sheet material should be ejected from the apparatus to give a rounded shape only when the front edge of the blank 2 of sheet material reaches the intersection point M '.

 Presented in FIG. 1a-c, geometric relationships are only exemplary. For example, depending on the fact that the place for the subsequent blank from sheet material should be larger or smaller, the forward moving blank from sheet material later or earlier deviates from the circle of folding; likewise, it is not necessary (but desirable) to provide a circle with the same radius of curvature as the circle of curvature A as the ejection circle B.

 FIG. 2 shows schematically and very simplistically a device or apparatus for rounding 80 for implementing the method in accordance with FIG. 1a-c. The rounding apparatus 80 has a coiling device 10 with the aforementioned pressing position P. Corresponding to the coiling circle A, the most well-known coiling device 10 for the sake of simplicity in FIG. 2 is not presented in more detail. In addition, the apparatus 80 for rounding has guide means 70 for guiding the rolled preform 1, 2 of sheet material, the inner circular mandrel 20 and the outer guide 30 together form a circular gap 40, which is closed by the end stop 31. In addition, the apparatus 80 for rounded shape is equipped with the already mentioned, oriented in a circle ejection B ejector mechanism, of which in FIG. 2, only two ejecting stops 50.1 and 50.2 are shown. The push stops 50.1 and 50.2 act in the axial direction, i.e. perpendicular to the area of the drawing. For the ejector stops 50.1 and 50.2, corresponding recesses 22, 37, 36 are provided in the guide surfaces of the inner circular mandrel 20 or the outer guide 30. Of course, other ejector means could be used instead of the ejector stops 50.1, 50.2.

 The circular gap 40 has two sections 41, 42. The first section 41 allows the blank 1 or 2 of sheet material to enter the coagulation position, that is, it corresponds to the coagulation position and contains a section of the coagulation circle A; it ends at the intersection point M 'of both circles A and B. The second portion 42 begins at the intersection of M', contains the portion of the ejector circle B and ends with the end stop 31. Sections 41, 42 are limited to the inner mandrel 20 and the outer guide 30. The inner circular mandrel 20 has an oval cross-sectional shape, which corresponds to the overlapping zone of circles A and B. The outer guide is made mainly in the form of a hollow cylinder, and its cross-section corresponds to the ejection circle B.

 The offset between the coagulation circle A and the ejection circle B, i.e. the distance between the centers A 'and B' of the circles can be selected, for example, in such a way that the blank 1 or 2 of the sheet material included in the folding circle A does not conflict with the pushing stop 50.2 on the entrance side.

 Described in connection with FIG. 1a-c, a coagulation method that can be implemented using the device in accordance with FIG. 2, is the simplest variant of the method in accordance with the invention and needs a zone of circular clearance 40 in a minimum of the guide surfaces (theoretically only in the end guide after the intersection point M '). This option can be used for blanks of sheet material with sufficient intrinsic stability and elasticity. Own stability mainly depends on the modulus of elasticity of the sheet material used, the thickness of the sheet material, the size of the blank from the sheet material, and the desired rounding radius. For coiled blanks of sheet material with little intrinsic stability (for example, of thin sheet material), it is preferable to provide other guide means, in particular for the first phase of coagulation and for the final phase. The method thus expanded and the corresponding device are described in conjunction with FIG. 3-9.

 FIG. 3 represents another embodiment of a device in accordance with the invention for folding sheet metal products. Equally acting elements already known from the previous drawings are again denoted by the same reference numerals.

 The device 10 for rounding is in accordance with FIG. 3 a rounding wedge 11, an inner rounding roller 12 and an outer rounding roller 13. Both rounding rolls 12, 13 are pressed against each other and act on the blanks passing between them (not shown in Fig. 3) along a line perpendicular to the plane of the drawing at the position pressing P in such a way that initially the flat blanks of the sheet material are bent along the desired constant radius corresponding to the rolling circle A.

 The outer guide 30 has a middle portion 34, as well as an end portion 35 that has an end stop 31. In addition, the outer guide is equipped with a holding member 32. The holding member 32 is equipped with a guide surface 33, a hook-shaped groove 38, and an arcuate bearing surface 39.

 The principle of operation of the holding member 32 is described below using FIG. 6-9. Between the retaining element 32 and the middle part 34, or between the middle part 34 and the end part 35, there are recesses 36 or 37 in which the pushing stops 50.1 or 50.2 move. The recess in the inner circular mandrel 20, opposite the recess 37, is again indicated by 22. The guide surfaces of the outer guide 30 directed to the circular gap 40 are everywhere located outside the ejection circle B, which determines the transportation position of the finished rolled product from sheet material. In accordance with FIG. 3 these guide surfaces are polygon shaped.

 In this embodiment, the inner circular mandrel 20 has a zone protruding beyond the coagulation circle A into the circular gap 40.

 The principle of operation of the device in accordance with FIG. 3 is described below using FIG. 4-9, which, by analogy with FIG. 1a-c schematically show another variant of the method implemented in this device in accordance with the invention, however, in six successive phases. Active surfaces in the corresponding phase, indicated by hatching in the pattern of FIG. 3, are indicated by dashed lines of the corresponding parts of the device.

 In accordance with FIG. 4, the leading part of the preform 1 from the sheet material has already passed the pressing position P and is guided with the help of the inner mandrel 20 extending beyond the coagulation circle A of the zone 21. As a result, the rounded part of the preform from the sheet material is easily deformed and is pressed against the guide surface 21 'due to its elasticity . Due to this, even with a one-way direction, a precisely defined position of the front part of the workpiece made of sheet material is obtained. Equally active in this phase is the guide surface 11 'of the rounded wedge.

 In accordance with FIG. 5, the front part of the blank 1 made of sheet material has reached the portion 42 of the circular gap 40 (Fig. 3), and there it is mainly guided by the outer guide surface 34 'along the ejection circle B and is thereby squeezed from the guide surface 21'.

 FIG. 6 shows the phase of the rolling method immediately after the end edge of the rolled sheet metal product 1 has left the pressing position P. The end zone of the sheet metal blank 1 is still guided by the guiding surface 33 ′ of the holding member 32 in the rolling circle A. Due to its kinetic energy, the blank 1 of the sheet material moves further in the circular gap 40, is guided in the ejection circle B using the inner and outer guide surfaces 20 ', 34', 35 'of the inner her mandrel 20 or the outer guide 30. The guide surface 33 of the retaining element 32 is designed so that the end edge of the blank 1 of sheet material has not yet reached its end when the front edge abuts against the end stop 31.

 FIG. 7 and 8 show how the blank 1 of the sheet material is deposited as a result of the impact on the end stop 31 (Fig. 7), so that the end edge of the blank 1 of the sheet material moves along the guide surface 33 'and finally leaves it, after whereupon the next portion of the blank 1 from the sheet material is released to the ejection circle B (Fig. 8). It is expected that the next part will spring and extend beyond the ejection circle B, and it is preferable to limit this spring movement with the arcuate bearing surface 39 'of the holding member 32. If, as a result of an impact on the end stop 31, the blank 1 of sheet material is deposited strongly A particular advantage is the polygonal shape of the outer guide surfaces 34 'and 35', as shown in FIG. 3, since the blank 1 of the sheet material is deflected into the resulting expansion of the circular gap 40 and can better spring.

 In an embodiment not shown, the blank of sheet material is moved forward in a rolling circle A until it is braked sharply with an end stop or other appropriate means, after which the rear end moves along surface 33 'only because of its kinetic energy and gets into the retaining element. Elastic deformation of the front of the sheet material blank is, in principle, absent, however, it can be provided as an additional tool.

 In FIG. 9 shows the last phase, the ejection phase. The rear end of the blank 1 of sheet material, which is gripped by the supporting surface 39 'and squeezed, is held in a hook-shaped groove 38', which is located on the ejection circle B, which prevents its reverse movement. Thus, already another blank 2 of sheet material can initially freely move forward along the guide surface 33 of the retaining element in a circle of curling A. Finished rolled product 1 of sheet material, the position of which is now precisely defined, can be pushed out of a circular gap. Preferably, the polygonal shape of the outer guide 30 facilitates easy ejection.

 As already mentioned, the method in accordance with FIG. 4-9, using the additional direction in the end zone and the direction of the next next edge in the end zone, is preferable for blanks of sheet material with relatively low intrinsic rigidity. In particular, from FIG. 7-9 it follows that the method in accordance with this option (as opposed to the variant in accordance with Fig. 1a-c) uses, along with the spring stress of the rolled sheet product, its kinetic energy to move the next next part along the ejection circle B, i.e. in the transport position. For this reason, this method must also be preferred for low-spring blanks of sheet material.

 Another possible course of action is based on the idea of using, for elastic deformation of the sheet material and the resulting leaving the pressing position P, the released end section to the transport position only of the kinetic energy of the subsequent part of the sheet material obtained by shock stop, without preliminary deformation of the front section blanks from sheet material. To implement this option, which is not shown in the drawing, only the end stop located in front of the pressing position P is needed, as well as the holding element for the transport position, for example, in the form known from FIG. 3 holding elements 32.

 Along with the presented displacement of the ejection circle defining the transport position B in the feed direction Z and the corresponding elastic deformation of the front section of the blank from the sheet material inward, it would also be possible to choose another transport position. So, for example, it would be possible to deflect the front section of the billet of sheet material outward with the help of an internal guide, for example, a round inner mandrel, respectively, instead of the outer guide 30, and accordingly deform elastically, and then also end section elastically emerging from the device 10 for rounding move to the transport position relative to the coagulation position inside, and the coagulation position would be released for the next blank from the sheet th material.

Claims (18)

 1. The method of folding products from sheet material in the apparatus to give a rounded shape, which consists in the fact that they carry out sequential feeding directly into the apparatus several consecutive blanks of sheet material, in a rounding device the workpiece from sheet material is plastic deformed, translate it into natural coagulation position and pushed out of the apparatus for giving a rounded shape, characterized in that before the finished rolled products are pushed out of the apparatus for giving rounded, immediately after coagulation of the workpiece from sheet material, at least its rear end portion is transferred from the coagulation position to the transport position, while freeing up the coagulation position, at least for the front of the next, already in the process of coiling the workpiece from sheet material.  2. The method according to claim 1, characterized in that at least one portion of the already rounded zone of the sheet metal product that is in the process of coagulation is rejected by means of guides during elastic deformation from the coagulation position, while the section directly exiting the rounding device the sheet material is held by deflecting forces under load, and after the complete passage of the sheet material through the rounding device at this load is transferred to the transport position.  3. The method according to claim 1 or 2, characterized in that by means of a retaining element, the part of the blank from the sheet material transferred to the transportation position is prevented from returning to the folding position.  4. The method according to claim 3, characterized in that the movement to the transport position of the preform of the sheet material is carried out by elastic deformation along the retaining element located in its path and then held by this element, preferably by the type of counter support.  5. The method according to any one of claims 1 to 4, characterized in that the front end of the sheet material blank coming out with a rounding device is braked by means of damping the feed speed, while the sheet metal blank with kinetic energy of its subsequent zone is elastically deformed so that its trailing end edge extends forward a certain amount relative to the natural end position during elastic deformation of the workpiece from the sheet material, and then when squeezing the eye is secured in the transport position and held there by means of a holding element.  6. The method according to claim 2, characterized in that the rounded area of the preform held in the rolled up position of the sheet material first passes the first section of the path corresponding to the folding position and then falls onto a second section of the path different from the folding position so that the section of the blank of sheet material deviates from the coagulation position.  7. The method according to claim 6, characterized in that the second section of the path is located between the corresponding section of the natural position of the coagulation and the center of curvature and that the rolled blank from the sheet material after it has passed the rounding device is freed due to the fact that its rear zone moves outward to the transportation position.  8. Device for coagulation of products from sheet material, comprising means for feeding individual blanks from sheet material, having a rounding device with an inner round mandrel, a device for shaping a round shape, an ejection mechanism for pushing finished products rolled from sheet material, a machine for shaping a round shape, characterized the fact that it is equipped with means of translation into the transport position, at least leaving the rounding device of the released rear end portion of the blank of sheet material.  9. The device according to claim 8, characterized in that the means of translation into the transport position is made with the possibility of elastic deformation of the workpiece made of sheet material emerging or leaving the rounding device.  10. The device according to claim 9, characterized in that the means of translation into the position of transportation and elastic deformation of the workpiece made of sheet material are equipped with a device for drastically inhibiting the feed rate of the workpiece made of sheet material leaving or leaving the rounding device, preferably with an end stop.  11. The device according to claim 9 or 10, characterized in that the means of translation into the transport position are equipped with a retaining element for holding at least the rear portion of the sheet material blank.  12. The device according to any one of paragraphs.8 to 10, characterized in that the means of translation into the transport position are equipped with a guide for elastic deformation of the sheet material blank, with which the front section of the sheet material blank exiting from the rounding device can deviate from the natural folding position .  13. The device according to p. 12, characterized in that the apparatus for giving a rounded shape is equipped with guide means for exiting from the rounding device blanks of sheet material, part of which is formed by an outer guide that acts on the front section of the blank from sheet material.  14. The device according to p. 13, characterized in that the outer guide mainly covers the transport position determining the ejection circle, the radius of which corresponds to the radius of curvature, and its center is offset from the center of the curl circle corresponding to the natural curl position, preferably in the feed direction of the sheet material.  15. The device according to claim 11 or 12, characterized in that between the outer guide and the inner circular mandrel, a circular gap is formed to accommodate the portion of the sheet material coming out of the rounding device, the part of the circular gap being made in the form of a guide gap for the elastically deformed front portion of the workpiece of sheet material, and the cross-section of the inner circular mandrel preferably corresponds to the main overlapping zone of both circles.  16. The device according to 14 or 15, characterized in that the outer guide is made polygonal, and the inner circular mandrel preferably has a guide zone protruding beyond the circle of coagulation in front of the guide gap for the portion of the workpiece made of sheet material emerging from the rounding device.  17. The device according to paragraphs. 10 and 11, characterized in that the end stop, as well as the retaining element are interfaced with the outer guide.  18. The device according to claim 11, characterized in that the holding element has an arcuate bearing surface to limit due to elastic deformation of the spring movement of the released section of the sheet material blank in the ejection circle and to accelerate fixation into the groove of the holding element.

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