EP0610108A1 - Crimping ring and method of making it - Google Patents

Abstract

Crimping ring constituted by a portion of metal band, wound on itself, the two ends of which are connected together without causing the appearance of an appreciable additional thickness in the connection area. The ends of the band (1) are arranged substantially in contact with each other along their terminal edge (4a, 5a), the thickness of each of the said ends being approximately half the thickness of the band. Their internal face is offset towards the outside with respect to the internal surface of the ring so as to constitute a housing (11) for a plate (8), the thickness of which is approximately half that of the band. A set of studs (6, 7) and of complementary holes (9, 10) is provided on the ends of the band and on the plate, the said studs being engaged in the holes and their free end being riveted onto the element opposite the one which bears them. <IMAGE>

Description

It is known that the fixing of two tubular elements fitted one inside the other is carried out in many cases by means of a closed annular ring which, after its positioning on the external tubular element in a zone opposite of the inner tubular element, is subjected to a constriction operation to ensure the proper tightening of two tubular elements.

Such shrinking rings are currently obtained by various methods.

Examples include the technique of stamping a flat metal ring, then cutting out the flat part that remains after the stamping operation. Such a process, in addition to its relative slowness, leads to a significant loss of metal during the trimming operation and therefore results in a prohibitive price for the ring to be shrunk.

On the other hand, it will be noted that it is possible to obtain rings to be constricted by cutting, according to a suitable width, a tube produced from a metal sheet wound on itself and welded along a generatrix of said tube. This process is also unsatisfactory. Not only does it require a relatively long time due to cutting, but also it requires prior manufacture of the tube, which again makes the price of the rings to be shrunk prohibitive.

After the development of the two known processes which have just been mentioned, we had the idea of making rings to be shrunk from a metal strip whose width corresponds to that desired for the ring. A portion of strip is cut and wound on itself and its two ends are linked to each other without making any noticeable excess thickness in the connection zone, which would be likely to disturb the subsequent execution of the constriction .

To this end, it has been proposed to weld edge to edge the two ends of the portion of the strip after it has been wound on itself. However, this operation cannot, in general, be carried out automatically on the machines used to cut the portions. tape and roll them up. This results in a discontinuity in the manufacturing process, as well as a certain brittleness of the welding area. Furthermore, the need for a welding operation prevents the use of a strip of metal suitably treated for the subsequent necking operation. The treatment in question must nevertheless be carried out after the manufacture of the ring, which, once again, results in a prohibitive price for the latter.

Still in the case of manufacture from a metal strip, we finally had the idea of cutting the ends of a portion of strip according to complementary profiles, for example in T , capable of being embedded one in the other, their immobilization, in the radial direction, being obtained again by a weld, generally at the ends of the horizontal bar of the T- profile. However, in addition to the drawbacks, already mentioned, resulting from the need for a welding operation, it has been found that during the shrinking operation, unacceptable deformations often occur on the rings obtained by this latter process.

The Applicant has had the idea of producing rings to be shrunk without any welding, eliminating the drawbacks of known rings, in particular those obtained by the first aforementioned process. To this end, the applicant proposes the implementation of methods which only require stamping and / or stamping, cutting and / or folding operations which can be automated. Furthermore, the absence of welding makes it possible to use a strip of metal suitably treated for the subsequent necking operation, which contributes to considerably reducing the manufacturing time of a ring and, consequently, its price. come back.

The invention therefore firstly relates to a new ring to be constricted formed from a portion of metal strip wound on itself.

According to the invention, the ends of the portion of strip wound on itself are arranged substantially in contact with one another along their terminal edge. The thickness of each of the two ends is close to half the thickness of the strip and their inside (or outside) face is offset towards the outside (or inside) relative to the inner (or outer) surface of the ring. Thus is formed a housing for a plate whose thickness is close to half that of the strip. A set of studs and complementary holes is provided on the ends of the strip and on the plate, said studs being engaged in the holes and their free end being riveted on the element (plate or end of the strip) opposite that which wears them.

The subject of the invention is also a method for manufacturing the rings to be constricted which have just been defined, according to which, in a continuous metal strip, two ends of two rings are produced simultaneously by stamping and / or stamping, each of '' They with at least one stud (or at least one hole), then we proceed to the simultaneous cutting of the extreme end edges, in the axial direction, of said ends

Thanks to all of these provisions, the usual requirements for the absence of any appreciable excess thickness in the connection zone of the ends of the strip portion are satisfied, while avoiding or limiting the loss of metal, while said connection zone has, in particular due to the existence of the plate, sufficient robustness to avoid the risks of an inadmissible deformation during the operation of shrinking the ring. In this regard, it will be noted that the plate can be easily produced from a material different from that of the strip, for example from a material whose mechanical resistance is greater than that of the material of the strip. In addition, it has been determined that, thanks to the invention, the direct cost (material and labor) of manufacturing a ring to be shrunk can be divided, all other things being equal, by three or even five compared to that which results from known techniques.

• · La figure 1 est une vue en plan d'une portion de bande métallique après l'opération d'emboutissage et/ou d'estampage pour la formation de ses extrémités
• · La figure 2 est une vue suivant la flèche F de la figure 1
• · La figure 3 est une vue en plan d'une plaque destinée à lier les deux extrémités de la bande
• · La figure 4 est une vue partielle en élévation d'une bague, avant la liaison des deux extrémités de la portion de bande qui la constitue
• · La figure 5 est une vue partielle en élévation d'une bague, après la liaison des deux extrémités de la portion de bande qui la constitue
• · La figure 6 est une section par un plan radial de la bague (suivant VI-VI de la figure 5) dans la zone de liaison des extrémités de la portion de bande
• · La figure 7 est une vue partielle en plan d'une bande métallique au cours du processus de fabrication des bagues selon l'invention
• · La figure 8 est une vue, suivant la flèche F' de la figure 7, avec arrachement partiel, de la bande qui y est représentée.

The invention will be better understood and its advantages as well as various secondary characteristics will become apparent from the following description of an embodiment. For this purpose, reference is made to the accompanying drawings in which

• · Figure 1 is a plan view of a portion of metal strip after the stamping and / or stamping operation for the formation of its ends
• · Figure 2 is a view along arrow F of Figure 1
• · Figure 3 is a plan view of a plate for joining the two ends of the strip
• · Figure 4 is a partial elevational view of a ring, before the connection of the two ends of the portion of strip which constitutes it
• · Figure 5 is a partial elevational view of a ring, after the connection of the two ends of the strip portion which constitutes it
• · Figure 6 is a section through a radial plane of the ring (along VI-VI of Figure 5) in the area of connection of the ends of the strip portion
• · Figure 7 is a partial plan view of a metal strip during the manufacturing process of the rings according to the invention
• · Figure 8 is a view, along arrow F ' of Figure 7, with partial cutaway, of the strip which is shown there.

If we refer first to FIGS. 1 and 2, we see a metal strip 1 having two ends designated respectively by the general references 2 and 3 . It will now be indicated, with reference to FIG. 4, that during the winding of the strip portion 1 , the lower faces 2 a , 3 a (in FIGS. 1 and 2) of the ends 2 and 3 are in the extension from each other to form the outer surface of the ring, their end edges being substantially in contact with each other. In what follows, we will designate by " external face ", the lower faces 2 a and 3 a (in FIG. 1) of the ends 2 and 3 by "internal face", those which are opposite them.

The reader has already understood and it will appear to him even more clearly in what follows that the "inner face" of the ends could without inconvenience be constituted by a lower face 2 a or 3 a , the "outer face" being still that which is his opposite. However, for the sake of clarity in the description, only the embodiment shown in the figures will be described, that is to say the case where the winding of the strip, in order to constitute the ring to be constricted, is carried out in the visible direction in Figures 4 and 5.

Returning to FIGS. 1 and 2, it can be seen that the ends 2 and 3 have substantially equal axial lengths l and their thickness, clearly visible in FIG. 2, is at most equal to half the thickness of the strip 1 .

The outer faces 2 a and 3 at ends 2 and 3 are continuous with the outer surface 1 a of the future ring, while the inner faces are designated by 4 and 5 respectively .

On the inner face 4 of the end 2 project four studs 6 , cylindrical or prismatic, whose axis is perpendicular to the inner face and whose height is at least equal to half the thickness of the strip 1 . On the inner face 5 of the end 3 also project four studs 7 similar to the studs 6 and, preferably, identical to these and arranged in the same way. Note however that the number of pads on each end is not imposed by the invention.

The end edges 4 a , 5 a in the axial direction, of the ends 2 and 3 or, more precisely, of their inner face 4 and 5 , are perpendicular to the axis of the strip 1 . However, as was shown in Figures 1 and 2, the internal terminal edges 4b and 5b, the inner surfaces advantageously have non-rectilinear profiles, preferably with an axial projection, whose function will appear later.

The strip portion 1 and the structure of its ends 2 and 3 having been described, the ring to be constricted is obtained by winding the strip portion 1 on itself (FIG. 4), as already indicated. Terminals 4 edges, 5a of the two ends 2 and 3 then come substantially into contact with each other and bonding the both ends in the circumferential direction of the ring, is obtained by means of a plate 8 visible in FIG. 3.

The plate 8 , of substantially rectangular shape, has a width equal to that of the strip 1 and a thickness close to half that of the strip. Its length is itself substantially equal to 2 l , that is to say twice the axial length of each end 2 , 3 . Its terminal edges 8 a have non-rectilinear profiles, complementary to those of the internal terminal edges 4 b , 5 b , of the faces interior 4 , 5 of the two ends of the strip. Finally, in the plate 8, two sets of four holes 9 and 10 are formed , the diameter and the relative arrangement of which are complementary to those of the two sets of studs 6 and 7 of the ends 2 and 3 .

After winding of the strip 1 , and as shown in FIG. 4, the ends 2 and 3 constitute a housing 11 for the plate 8 which can be embedded therein, the studs 6 and 7 penetrating into the holes 9 and 10 . The free ends of the studs are fixed on the face of the plate 8 located in the extension of the inner surface of the ring (Figure 5) and this mounting plate and the cooperation of the complementary profiles of its end edges 8a with edges terminals 4b, 5b of the housing 11 ensure perfect continuity of the ring and good strength.

It will be indicated here that the material of the plate 8 is indeed advantageously the same as that of the strip, but that it will have undergone an appropriate treatment such as work hardening, so that its mechanical resistance (or its hardness) is, preferably close to twice that of the strip material. Anyway, whatever the nature of the material of the plate and its relative resistance compared to that of the material of the strip, one can easily define the depth of the housing 11 and the corresponding thickness of the plate 8 to obtain the characteristics mechanical properties desired for the connection of the two ends 2 and 3 of the strip 1 .

The ring to be shrunk is then finished and ready for use, the stamping and / or stamping and riveting operations having not affected the properties of the metal of the portion of the strip 1 , chosen as a function of the 'subsequent use for a constriction operation, while the bonding zone of the ends of the strip has a flexural strength and a compressive strength at least equal to those of the current part of the strip.

Referring to Figures 7 and 8, we will now expose, insofar as they have not already appeared to those skilled in the art, the main characteristics of the process allowing the rapid and economical manufacture of the ring to be shrunk of the type previously described.

Starting from a strip 21 of suitable metal and suitably treated for its subsequent use, a group, designated by A , constituted by one end 22 of a, is produced simultaneously, by a stamping and / or stamping operation. a ring and an end 23 of another ring. Each of these ends obviously has the structure described above and in particular a thickness at most equal to half the thickness of the strip.

During this operation, the metal of the strip is pushed back on the lateral edges of the ends 22 and 23 as can be seen in FIG. 7. In a later phase of the process, the pushed back metal (represented in dotted line) on the edges of the ends 22 and 23 will be eliminated, for example by cutting, to give them a width equal to that of the strip 21 .

When at least two consecutive groups, such as A and A₁ , have been produced, leaving between them portions of band B B₁ etc ... of suitable length, corresponding to the desired circumference for the rings to be shrunk, we proceed , preferably before winding the strip portion B located between the two groups A and A₁ , at the same time cutting the extreme end edges of the portion B, that is to say that the cutting is carried out substantially in the middle portions A and A₁ .

After the strip B portion has been completely wound up , its ends 22 and 23 are assembled as described above with reference to FIGS. 4 and 5, by means of a plate, previously prepared, of the type of that described in reference to figure 3.

However, we can also prefer to fix the plate first on one end of the strip, by riveting the corresponding studs and then proceed to wind the strip and finally finish the ring by fixing the plate to the 'other end, by riveting the corresponding studs.

Although the description of the ring to be constricted and its manufacturing process was made assuming that the studs 6,7 are arranged on the ends 2,3 of the portion of the strip 1 and the holes 9,10 on the plate , it is obvious that this provision could be reversed. We can even consider, without departing from the scope of the invention, to have a set of holes and a set of studs on a plate 8 and the complementary sets of studs and holes on the ends 2 and 3 of the strip portion 1 .

Claims (6)

Ring to be constricted constituted by a portion of metal strip, wound on itself, the two ends of which are linked to each other without showing any appreciable excess thickness in the connection zone, characterized in that the ends ( 2 , 3) of the portion (1) of strip are disposed substantially in contact with each other along their terminal edge (4a, 5a), the thickness of each of said ends being close to half the thickness of the strip and their inside ( 4,5 ) (or outside) face being offset towards the outside (or inside) with respect to the inside (or outside) surface of the ring so as to constitute a housing ( 11 ) for a plate ( 8 ) whose thickness is close to half that of the strip, while a set of complementary studs ( 6,7 ) and holes ( 9,10 ) is provided on the ends ( 2,3 ) of the strip and on the plate ( 8 ), said pads being engaged d ans the holes and their free end being riveted on the element (plate or end of the strip) opposite to that which carries them. Restricted ring according to claim 1, characterized in that it comprises a set of at least two studs ( 6,7 ) (or holes) arranged on each of the ends ( 2,3 ) of the strip and as a set of at least four holes ( 9,10 ) (or studs) arranged in correspondence on the plate. A shrinking ring according to claim 1, characterized in that the plate ( 8 ) is made of a material of mechanical resistance greater than that of the strip ( 1 ). Restricted ring according to any one of the preceding claims, characterized in that at least one of the end edges ( 8 a ) of the plate has a non-rectilinear profile and in that the corresponding end ( 4 b , 5 b ) of the housing ( 11 ) has a complementary profile. Method for manufacturing a shrink ring according to any one of Claims 1 to 4, characterized in that, in a continuous metal strip, the two opposite ends of two rings are produced simultaneously by drawing and / or stamping, in view to give them a thickness close to half that of the strip and to reveal in each of them at least one hole (or at least one stud), and in that one then proceeds to the simultaneous cutting of the extreme end edges, in the axial direction, of said ends. A method according to claim 5, characterized in that the metal pushed back on the lateral edges of the ends of two rings is removed, for example by cutting, to give said ends a width substantially equal to that of the strip.

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