FR2728814A1 - Machinery component made from folded strip material - Google Patents

Abstract

The component is made of an initial metal strip or tube folded to form sections (e1-e3) of different thicknesses depending on the number of times the strip or tube is folded. The folded layers of material can be set close together, with no gaps between, or they can be separated by inner spaces. The size of the spaces depends on the distance between the outer surfaces of the folds. The strip or tube is selected to make the required component according to the desired final thicknesses. It is then bent for the appropriate number of times, applying compression forces sufficient to give the component sharp edges.

Description

PIECE OBTAINED BY FOLDING A STRIP
Ductile materials make it possible to obtain long parts with simple or complex section, in particular by means of dies, or by hot or cold profiling.

 When it comes to creating steel parts, the starting element is a large bar, or "billet", with a square section, 100 millimeters on a side for example, and the section is gradually reduced, by means of pebbles, after heating it to make it more malleable.

 The reduction in section is necessarily accompanied by an elongation, so that the machining involves the billet according to the three dimensions of one space.

 As the billets are standard and the only important criterion is the respect of the dimensions of the section, the length of the profiled parts obtained is variable according to the section of each part.

 Depending on the case, we obtain a larger number of pieces than necessary and we store them or else we have false cuts which constitute as much scrap.

 The present invention overcomes these drawbacks by making it possible to create parts of finite length, without excess or scrap, because the machining only concerns the section and leaves the length of the starting element intact, length only the we can calculate precisely in order to achieve significant material savings.

 To this end, the invention relates to a part of the type having parts such as wings forming angles between them, like the profiles, characterized in that it is formed of a band folded on it- same and constituting the parts according to a thickness whose value depends on the number of folds of the strip, a value which can be either the same for all the parts, or different according to the parts.

According to other characteristics of this room
- the folds of the strip are applied against each other, without intervals;
- At least some of the folds of the strip are separated by a space, the value of which depends on the distance separating the outer faces of the folds of the strip located face to face.

 The invention also relates to a method for the manufacture of a part of the type having parts forming angles between them, like the profiles, characterized in that one chooses a strip whose thickness is coordinated to that which at least certain parts of the part must have, the strip is folded as many times as necessary to constitute the parts of the part, if necessary by superimposing at least two thicknesses of strip to give at least one of these parts a thickness greater than that, nominal, of the strip.

According to other characteristics of this process
- The strip is a sheet such as a metal strip;
- the strip is a tube;
- After having formed the part by folding, it is subjected to compressive forces capable of creating edges as sharp as possible in place of at least some of the rounded edges originating from the folding of the strip.

 The invention will be better understood from the detailed description below made with reference to the accompanying drawing. Of course, the description and the drawing are given only by way of an indicative and nonlimiting example.

 Figure 1 is a schematic perspective view of a strip segment intended to be folded longitudinally to provide a part according to the invention.

 FIG. 2 is a schematic front view, on a larger scale, of the strip segment of FIG. 1.

 Figures 3 to 6 are schematic front views of the strip segment of Figure 2, at certain intermediate characteristic stages of longitudinal folding.

 Figure 7 is a schematic front view of a part according to the invention.

 Figures 8 and 9 show two alternative embodiments of the part of Figure 7.

 Figures 10 to 12 are schematic front views of other parts according to the invention.

 Figure 13 is a schematic sectional view showing two parts according to the invention fixed to sheets and forming part of a metal louver.

 Figure 14 is a schematic front view of a tube intended to be compressed and folded longitudinally to provide a part according to the invention.

 FIGS. 15 to 17 are schematic views of the faces of parts in accordance with the invention, obtained from the tube of FIG. 14.

 Referring to Figure 1, we see a strip of strip 1 of width L and of indefinite length since it is formed by the end of a long strip wound in a coil (not shown).

 The segment is intended to be folded longitudinally by means of a machine of known type and, therefore, within the reach of those skilled in the art, comprising means for guiding the strip and rollers judiciously placed on the path of the strip to force the latter to straighten or lower gradually, in several stages.

 As will be seen below, the mechanical operations which constrain the strip only concern its width and its section.

 The length of the segment worked can be the end of a coil which unwinds as the strip advances, the latter being cut transversely at the end of the cycle to give the finished part its final length.

 But the segment worked can also be made to its length by transverse cutting before being engaged in the machine intended to fold it longitudinally.

 This arrangement is very advantageous in comparison with the hot rolling operations currently used to transform a large short part into a small long part.

 FIG. 3 represents the segment of FIGS. 1 and 2 after successive foldings which give it a margin 2 folded over a large face 3, connected to another large face 4 by a flap 5, the large face 4 having a flap 6.

In Figure 4, new longitudinal folds have been created in the large faces to create
- in the large face 3 a pan 7 and a return 8
- in the large face 4, a return 9.

 It is observed that at the stage of FIG. 4, all the longitudinal folds have been created. The following operations therefore consist exclusively in increasing the folding, which is particularly visible by comparing FIG. 4 to FIG. 5.

 On this one, we see that we must first fold the return 9 carrying the flap 6, according to the arrow F1, so that the return 9 is placed against the large face 4 and the flap 6 against the pan 5.

 In Figure 6, this position is reached, so that we can now fold the pan 7 carrying the return 8 and the margin 2, according to arrow F2.

 When this is done, the part is finished, as shown in Figure 7.

 It can thus be seen that starting from a strip of given nominal thickness, for example 1 millimeter, it is possible to obtain parts whose different constituent parts have thicknesses exactly suited to the use for which the finished part is intended.

With the example shown of a part having a substantially S-shaped section, it can be seen that
- the right wing has a thickness el equal to twice the nominal thickness of the strip, namely 2 millimeters, if 1 the thickness of the strip is 1 millimeter, since it is formed by the superposition of the face 3 and pan 7,
the left wing has a thickness e2 also equal to twice the nominal thickness of the strip since it is formed by the superposition of the face 4 and of the return 9,
the central core has a thickness e3 equal to four times the nominal thickness of the strip since it is formed by the superposition of the pan 5, the flap 6, the return 8 and the margin 2.

We understand that if we wanted this same piece to have a greater thickness, in particular for reasons of mechanical strength and / or rigidity, we could have chosen a strip of 1.2 mm, 1.5 mm, etc., in which case we would have had
- el = 2.4 or 3 millimeters,
- e2 = 2.4 or 3 millimeters,
- e3 = 4.8 or 6 millimeters.

 Given the mechanical stresses imposed on the strip during folding, it may happen that a given final structure is impossible to obtain beyond a certain nominal thickness, which means that for the same general final shape, it is possible to adopt different folds.

 Thus, for example, Figures 8 and 9 show exactly the same part as that of Figure 7 but obtained with different folds.

 It is observed that the part of FIG. 7 presents no solution of continuity since the end 10 of the flap 6 (one of the two longitudinal edges of the segment of FIGS. 1 and 2) is covered by the pan 7, that the end 11 (edge separating the margin 2 of the return 8) is applied against the return 9 and that the free end 13 of the return 8 (the other of the longitudinal edges of the segment of FIGS. 1 and 2) is applied against the pan 7.

 On the part of FIG. 8 there is a continuity solution 12, owing to the fact that the free ends 10 and 13 (longitudinal edges of the segment of FIGS. 1 and 2) are placed opposite one another, on the left wing.

 On the part of figure 9, there is no continuity solution because the free ends 10 and 13 are concealed (as in figure 7): the two free ends 10 and 13 are applied on the left wing .

 In FIGS. 10 and 11, a different part has been shown than that in FIGS. 7 to 9, the cross section of which is substantially in the form of a T with unequal wings and in FIG. 12 a T-piece with equal wings has been shown.

 Note that the part of Figure 10 has a continuity solution 12, the two free ends 10 and 13 being placed face to face on the right wing.

 It is understood that the invention makes it possible to create all kinds of shapes by the section of long or "profiled" parts.

 For ease of drawing, FIGS. 3 to 7 represent sharp edges between two folded parts but, in reality, the folding by rollers leaves small curved connecting leaves, as can be seen in FIGS. 8 to 12.

 For certain applications, these rounded edges are perfectly suitable and the parts of FIGS. 8 to 12 could be considered as finished.

 For other applications, these rounded edges are not recommended.

 This is the case, in particular, with metal shutters which are made up of sheet metal panels bordered by profiles.

 Figure 13 shows the central part of such a louver, where the two end leaves of the louver meet.

 The leaf 20 is formed by a panel of solid or perforated sheet metal 21 and by an S-shaped part 22 with unequal wings, conforming to the part shown in FIG. 8.

 The leaf 23 is formed by a panel of solid or perforated sheet metal 24 and by a T-shaped part 25 with unequal wings, conforming to the part shown in FIG. 10.

 The longest wing of parts 22 and 25 receives the corresponding sheet metal panel which is fixed to it by welding.

 Note that the sheet metal panels 21 and 24 completely cover the two continuity solutions 12, so that these lines of weakness are perfectly concealed and protected.

 To date, the shutter pieces corresponding to pieces 22 and 25 are obtained in a single solid piece, by hot rolling of a billet, so that sharp edges are obtained.

 It is therefore usual to see these pieces with clear edges, giving an impression of solidity and quality, and it would be disadvantageous to leave the connection leave visible here in FIGS. 8 and 10 for parts 22 and 25.

 For this reason, these parts are finished, after complete folding, by means of powerful mechanical tools, by the pinching of the external connection fillets, in order to crush them and thus create sharp edges, as is clearly seen in figure 13.

 We therefore benefit from the manufacturing process of the invention while making parts whose appearance is almost identical to that of traditional parts.

 Note that the internal leaves of parts 22 and 25 remain unchanged since they are neither accessible to the forming tools after complete folding, nor visible from the outside.

 Note that a part according to the invention being formed by the superposition of "layers" without intervals, this part has the same weight as if it were full, that is to say that if it had been manufactured with the classic process.

 According to an alternative embodiment of the invention, the starting product is not a flat strip but a tube 30 whose thickness E is chosen according to the same principle as that indicated above.

 The tube 30 is cut to the desired length either before forming or after since the machining has no influence on the length of the part.

 The tube 30 is crushed along longitudinal fold lines suitably placed according to the shape of the part to be obtained.

 In FIGS. 15 to 17, we see the example of three parts respectively of the type of those of FIGS. 10, 8 and 12.

 The wings having a thickness el and e2 equal to twice the thickness E of the tube 30, namely 2 millimeters, if E is equal to 1 millimeter, since they are formed by the superposition of two thicknesses of the wall of the tube 30 , by crushing.

 In FIGS. 15 and 16, the central core has a thickness e3 equal to four times the nominal thickness of the tube 30. However, the tube 30 having a closed section, it is not convenient, and sometimes it is impossible , to overlap two thicknesses twice.

 In addition, it may be desired to have lighter parts than traditional parts, while the embodiment of Figures 1 to 13 provides parts whose weight is equal to that of a conventional part.

 For all these reasons, voids can be provided where the thickness must be greater than that of twice the nominal thickness.

 For the part of FIG. 15, the folding then provides for creating a void 31 creating between the opposite faces of the faces 32 and 33 a space equal to twice E.

 I1 is the same for the part of figure 16, where a space 34 is equal to twice E.

 FIG. 17 illustrates a variant which would be impossible to produce from the tube 30, since the central core has a thickness e4 equal to three times the nominal thickness.

 This odd number is obviously impossible to respect by bending a tube which necessarily has two faces to be taken into account, and which can only give an even number of overlaps.

 The central space 35 is therefore equal to E.

 It should be emphasized that the presence of one or more spaces inside a room, makes it possible to give the finished piece, at the location considered, any external thickness beyond two nominal thicknesses since the space , respectively each space, can have any width, and not only a multiple of the nominal thickness as is the case of Figures 3 to 13 where all the "layers" are contiguous.

 Incidentally, such an odd number is easy to respect from a strip which is worked by unit thicknesses.

 Of course, the presence of spaces can be provided both from a strip and from a tube.

 The invention has multiple applications and can be implemented not only with metal but also with other materials, in particular composites, paper, cardboard, etc.

 The parts obtained can be profiles, as described and shown, or other elements of any length, depending on the field of application.

Claims (7)

 1- Part of the type having parts such as wings forming angles between them, like the profiles, characterized in that it is formed of a strip (1) folded on itself and constituting the parts according to a thickness (el, e2, e3, e4) whose value depends on the number of folds of the strip (1-30), a value which can be either the same for all the parts, or different according to the parts.  2- Part according to claim 1, characterized in that the folds of the strip (1) are applied against each other, without intervals.  3- Piece according to claim 2, characterized in that stinks at least some of the folds of the strip are separated by a space (31, 34, 35) whose value depends on the distance between the outer faces of the folds (32-33) of the tape located face to face.  4- Method for manufacturing a part of the type having parts forming angles between them, like the profiles, characterized in that one chooses a strip (1-30) whose thickness (eO- E)) is coordinated with that which at least certain parts of the part must have, the strip (1-30) is folded as many times as necessary to constitute the parts of the part, if necessary by superimposing at least two thicknesses of strip to give at least one of these parts a thickness (el, e2, e3, e4) greater than that, nominal (eO-E), of the strip (1-30).  5- Method according to claim 4, characterized in that the strip is a sheet such as a strip (1).  6- A method according to claim 4, characterized in that the strip is a tube (30).  7- A method according to claim 4, characterized in that after having formed the part by folding, it is subjected to compressive forces capable of creating edges as sharp as possible in place of at least some of the rounded from the folding tape (1-30).