CH288856A - Thin corrugated metal strip for forming tubes. - Google Patents

Description

Corrugated mined metal strip for forming tubes. 1:1 It is known to manufacture a tube, such as, for example, the outer conductor of an axial pair of an electrical communication cable, from a thin strip of metal having corrugations which are transverse with respect to the longitudinal axis of the Strip and whose purpose is to mechanically reinforce the tube for radial forces and to give it at the same time more flexibility.

The object of the invention is to constitute a thin metallic strip, in such a way that Fon can, from this Strip, form a tube of circular section which presents transverse undulations with respect to the axis of the tube, and which, a once formed, retains an invariable diameter. In the sequel, the operation which consists in making a tube from a strip will be referred to as interfacing.

The thin metal strip, object of the invention, which presents alternately convex and concave transverse corrugations, is characterized by the following points: ä, the width of the. bände, de teile So that there is a smooth border on each side of the strip.

2 At least part of the ripples have -one of theirs. ends terminated by a part perpendicular to the plane of the respective smooth edge of the strip, the sharp edges of the undulations thus produced being intended to constitute abutments for the formation of tubes.

3 The Planes of the two Smooth Edges are offset in the direction perpendicular to the face of the Strip by an amount at least equal to . the thickness of the metal strip. The offset of these planes may correspond to the depth of the undulations.

Thanks to this conformation, when the strip is knitted to form a tube, the two smooth edges mentioned above can overlap in parallel and thus close the tube, without any extra thickness occurring at this point. Each of the la@teral Edges of the Strip can come to lean against the. abutment formed by the ends of the corrugations on the other side of the Band; if a tube is thus closed, each of the lateral Edges of the Strip bears against a stop, one im from the inside of the tube, the other from the outside.

The tube thus formed can be maintained externally, for example by one or more ribbons, metallic or not, wound helically around it or by any other means.

The tube thus produced cannot be deformed, and its diameter is RTI ID="0001.0266" WI="16" HE="4" LX="1479" LY="2260"> determined invariably by the . abutment of each of the side edges of the strip against the ends of the corrugations on the opposite side of the strip; nor can it exert radial forces on elements that might be placed inside it.

The clean edge of a corrugation can be obtained, for example, by making a pure cut between the end of the corrugation and the smooth edge;. this cut can be made for example at the same time as the stamping of the corrugations.

The invention will be better understood from the description of the embodiments given below by way of non-limiting examples and from the attached drawings.

Figs. 1, 2, 3, 4, 5, 6, 7 and 8' relate to an exemplary embodiment where all the corrugations have one end forming a clean edge.

fig. 1 shows a perspective view of such a strip, the fia. 2 a quick shot of the fia band. 1, fia. 3 and 4 profile views of each side of the. fia band. 1, fia. 5- and 6 cross-sections (the band fia.<B>1.</B>

The fia. 7 and 8 show in section<B>the</B> tube formed from the strip of the fi;. 1, at the place of its closure.

The fia. 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18 relate to an embodiment where only part of the undulations have an end forming a raw edge.

The fia. 9 represents crumb, -view in perspective of such a strip, the fia. 10 a plan view of the fia strip. 9, fia. 11 and 12 profile views of each side (the strip of fia. 9, fia. 13, 14, 15 and 16 cross sections of the strip of fia. 9.

The fia. 17 and 18 show in section the tube formed from the strip of the fia. 9, at the place of its closure.

The fia. 19 shows the cross-sectional view of a coaxial pair, the outer conductor of which is produced by a corrugated strip. The fia. 1 shows in perspective a certain length of a metal strip 1, the middle part of which has convex undulations 2 and concave undulations 3, the edges 4 and 5 of the strip remaining smooth. All the corrugations are terminated at their projecting ends by a part perpendicular to the. respective smooth border; by way of example, this perpendicular part is shown made by means of a sheer neck; the figure clearly shows that the two smooth edges 4 and 5 are not in the same plane.

The fia. 2 shows in plan the part of the strip of FIG. 1; the ends of the convex corrugations perpendicular to the edge 4 are shown at 6, and the ends of the concave corrugations perpendicular to the edge 5 are. represented at 7, The .fia. 3 represents the fia band 1 profile. 2 seen in the direction of the. arrow f; in this figure the curved waves are seen above border 4.

The fia. 4 represents the profile of the band 1. of the fia. 2 viewed in the direction of arrow g; in this figure, the concave undulations are seen below border 5.

The fia. 5 shows the section of the strip 1 made along<I>ab,</I> that is to say passing through l a, the lower part of a concave undulation, and fia. 6 shows the section of strip 1 made along cd., that is to say passing through the apex of a convex undulation; fia them. 5 and 6 clearly show that the planes of the smooth border skies 4 and 5 are parallel to each other and that their distance is at least equal to the thickness of the metal strip.

The fia. 7 and 8 represent in section a part of the tube formed by the bending of the strip 1, at the location of the closure of the tube; these figures show the position taken by the borders 4 and 5 which overlap without there being any extra thickness either inside or outside the tube; cutting the tube on the fia. 7 corresponds to the section of the strip of FIG. 5, and fig. 7 shows, on the inside of the tube, the abutment of the edge 8 of the strip against the end 7 of the concave undulations 3; the section of the tube in fig. 8 corresponds to the section of the strip in FIG. 6, and fig. 8 shows the outer side of the tube the abutment of the edge 9 of the. band against the end 6 of the convex corrugations 2.

In Figs. 7 and 8 is shown, by way of example, a tape 10 wound helically around the tube formed from the tape 1 and maintaining it externally; the double abutment of the edges of the strip against the sharp edges of the corrugations ensures that the diameter of the tube cannot vary.

The. fig. 9 shows in perspective an embodiment of a certain length of a metal strip 11, in which only part of the corrugations have one of their ends forming a clean edge. Just as the band of fig. 1, the band 11 has convex and concave undulations in its middle part, the hard edges 12 and 13 remaining smooth; the convex corrugations 14 terminate at one end in a portion perpendicular to the smooth edge 12, and the concave corrugations 15 terminate at one end in a portion perpendicular to the smooth edge 13; the convex undulations 16 and the concave undulations 17 which are between the undulations 14 and 15 have no end forming a straight edge and they are preferably shorter than the undulations 14 and 15, so as not to interfere with the abutment of the edges of the strip against the ends forming. clean edge of the corrugations 14 and 15 when closing the tube.

fig. 10 shows part of strip 11 in plan; the ends of the convex undulations 14 perpendicular to the edge 12 are shown at 18, and the ends of the concave undulations 15 perpendicular to the edge 13 are shown at 19; the ends of corrugations 16 and 17 are shown at 20 and 21 respectively.

fig. 11 represents the profile of the strip 11 of FIG. 10 seen in the direction of the arrow f; convex corrugations 14 and 16 are seen above border 12.

fig. 12 represents the profile of the strip 11 of FIG. 10 seen in the direction of arrow g; the concave undulations <B>15</B> and <B>11</B> are seen below border 13.

Figs. 13 and 14 represent sections of the strip 11 opposite an undulation, the end of which forms a free edge, FIG. 13 being made in kl and passing through the lower part of a concave corrugation 15, and FIG. 14 being made in m, at and passing through the upper part of a convex corrugation 14.

Figs. 15 and 16 represent sections of strip 11 on the right. of a corrugation whose end does not form a clean edge, fig. 15 being made op and passing through the lower part of a concave corrugation 17, and FIG. 16 being made in qi- and passing through the upper part of a convex corrugation 16.

Figs. 17 and 18 show in section the tube formed from the strip 11 at the location of its closure; the section of the tube in fig.17 corresponds to the section of the strip in fig. 13 and the section of the tube in fig. 18 to 1_a section of fig. 14; at 10 is represented, as in FIGS. 7 and 8, a device serving to hold the tube externally.

The metal strip object of the invention can be used. form, for example in an electric telecommunication cable, the outer conductor of a coaxial pair or the screen of a symmetrical pair.

fig. 19 shows, by way of example, the longitudinal section of a coaxial pair, the outer conductor 22 of which is made from a strip according to the invention and forms a tube with corrugated walls of indefinite length on which is wound , as an example, a strip 10 serving to hold the tube externally; the phantom elements represent the central elements of the coaxial pair; these elements which do not form part of the invention are given by way of example, and it is quite obvious that the insulation of the coaxial pair shown in FIG. 19 by 90 insulating washers could be continuous insulation.

Claims (2)

CLAIM: Thin corrugated metal strip for forming tubes, having corrugations perpendicular to the direction of its length and the convexity of which is alternately directed towards one or the other face of the strip, characterized in that the length of the undulations is less than the. width of the strip, so that there remains on each edge thereof - soot smooth edge, in that the planes of the two smooth edges are offset in the direction perpendicular to the face of the strip by an amount at less equal to the thickness of this strip, and in that at least part of the corrugations have crumb of their extremities terminated by a part perpendicular to the plane of the respective smooth edge of -the strip, the clean edges of the corrugations thus xalized being intended to constitute stops during the formation of tubes. SUB-CLAIMS: 1. Band according to claim, characterized in that the depth of the undulations is at least equal to the thickness of this band. 2. Band according to claim, bent around an axis parallel to its length and thus forming a tube, characterized in that its two smooth edges overlap and in that each edge abuts. the parts perpendicular to the plane. of the other border terminating the undulations on the side of this other border.