Safety device
The flexible metal rope with collars addresses the issue of instability in metal ropes by locking the strands in place, preventing untwisting and enhancing resistance to cutting, while allowing limited bending.
Patent Information
- Application Number
- JP2024569008
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-05-20
- Filing Date
- 2023-05-19
- Publication Date
- 2025-05-30
AI Technical Summary
Metal ropes with helically wound strands can be easily broken by cable cutters that unwind the strands, leading to instability and potential untwisting.
A flexible metal rope with collars that clamp the rope at spaced positions along it, preventing substantial relative lateral movement of the strands and applying pressure to lock the path of the strands, thereby preventing untwisting.
The solution effectively prevents the untwisting of the metal rope strands, making it resistant to breaking by conventional cutters, and allows limited bending while maintaining structural integrity.
Smart Images
Figure 2025516909000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a safety device and has a particular application in safety devices where two ends of a long element must be held together.
Background Art
[0002] Such devices can be used to secure luggage and light vehicles in a manner described in various patent publications, including International Publication No. WO 2010 / 103327, International Publication No. WO 2015 / 087067, U.S. Patent No. 5,706,679, and U.S. Patent No. 6,510,717, the disclosures of which are incorporated herein by reference. The present invention is directed to such a long element in the form of a metal rope.
[0003] A metal rope or cable including helically wound strands is very strong, but can be broken relatively easily using a cable cutter that unwinds the strands, effectively allowing the strands to be cut individually. To stabilize the strands and prevent such unwinding, for example by a cable cutter or bolt cutter, the safety device according to the invention includes a flexible metal rope having a diameter in the range of 10 to 25 mm, the flexible metal rope including helically wound strands and having collars that clamp the rope at spaced positions along it. The spacing between the collars is less than or equal to the rope diameter, and each collar has a wall thickness in the range of 5 to 15% of the rope diameter. The axial length of each collar is typically less than or equal to the diameter of the rope. The collars engage the rope with sufficient pressure to prevent substantial relative lateral movement of the strands at each location. This pressure is typically in the range of 1 to 8 tons, and is typically at least 4 tons, preferably 5 to 8 tons. When the rope ends are fixed and installed so that the rope cannot untwist as a whole, the collars effectively lock the path of the strands between them. Although substantial relative lateral movement of the strands is prevented, it will be understood that some longitudinal movement is possible to allow the rope to be bent. However, the amount of bending allowed is limited and is determined by the pressure applied by the collars.
[0004] Typically, each color is a metal band fixed around the rope. This can take the form of a metal strip whose ends are drawn together to extend around the rope, or a closed loop having at least one laterally expanding portion crimped to extend around the rope. In a preferred embodiment, each color is a metal ring swaged to engage the rope with sufficient pressure. Swaging can, as a result, make the outer cross-section of each color polygonal, and a preferred swaging technique makes this cross-section hexagonal. A complementary tube portion can also be placed around the rope and swaged to form a color on the rope. In this way, the portions are press-connected. In a preferred swaging process, complementary tube portions of substantially semi-circular cross-section are used. Swaging in the creation of the rope for use in the device of the present invention can reduce the rope diameter by an amount within the range of 6-8%.
[0005] The metal rope used in the device of the present invention includes metal strands wound around a helically wound core. The strands themselves can include helically wound wires. The rope is preferably a compressed wire rope. As described above, the diameter of the rope is within the range of 10-25 mm, but a preferred rope has a diameter within the range of 12-22 mm. The metal used is usually high-tensile steel. However, in some applications, especially when the main purpose is to prevent the rope from loosening or untwisting, different materials, and even non-metals, can be used for either or both of the rope and the color.
[0006] In some embodiments of the present invention, a tubular element can be installed between the colors. The element can be shaped to receive the colors, and the juxtaposed surfaces of both the colors and the element ends are curved to allow limited bending of the rope adjacent to each color. The element itself can be compressible to accommodate such bending.
[0007] The ropes used in the present invention can be joined alongside each common or selected color to adjacent ropes. Such a configuration creates a strap with two or more ropes that can bend only in a plane perpendicular to the plane containing the ropes. The color may be common to three or more ropes or may be common to two or more ropes dispersed across the strap using the selected color.
[0008] The safety device according to the present invention makes it possible to prevent or at least limit the rotation of one end of the rope relative to the other end, avoiding the untwisting of the rope strands. Typically, it has complementary locking units at each end of the rope. To prevent the untwisting of the rope, the locking units are non-rotatably attached onto the rope ends and are adapted to engage so as to prevent relative rotation between them.
[0009] Here, the present invention will be described by way of example with reference to the accompanying schematic diagrams.
Brief Description of the Drawings
[0010]
Figure 1A
Figure 1B
Figure 2A
Figure 2B
Figure 3A
Figure 3B
Figure 3C
Figure 3D
Figure 3E
Figure 4
Figure 5
DETAILED DESCRIPTION OF THE INVENTION
[0011] The rope cross-section shown in Figure 1A includes metal strands 2 and 4 wound helically in two layers around a metal core 6, and the metal core 6 itself may include helically wound strands. Strands 2 and 4 may also include helically wound wires. Figure 1B shows a similar cross-section, but the wire rope is compressed. The preferred material used for the strands and wires is high-tensile steel. The compressed wire rope reduces its diameter by 10 - 20%. Thus, a rope with an initial diameter of about 15 mm can be compressed to about 13.5 mm.
[0012] Figure 2A shows a length of metal rope 8 having collars 10 in the form of simple rings spaced along it, each in the form of a metal band, before being swaged to clamp the rope. The spacing between collars 10 along the rope is less than or substantially equal to the rope diameter. In the example shown, the rope diameter and the spacing between collars are substantially the same at about 15 mm. The width or axial length of each collar is about 10 mm. Figure 2B shows the rope of Figure 2A after the collars have been swaged around the rope. This swaging reduces the rope diameter by 5 - 10%, usually 6 - 8%. As can be seen from the figure, the swaging has changed the outer cross-section of the collar, and the cross-section is shown as hexagonal. When the rope is installed as part of a locked safety device and large rotation or untwisting of the rope is prevented, the collar prevents the strands from unraveling and prevents the strands from spreading when attempting to break the rope with a conventional cable cutter or bolt cutter. As a result, the rope remains intact and, although it may eventually break, the rope slows down the process enough to prevent the attempt.
[0013] The collar 12 shown in FIG. 3A is a closed band having extensions 14 on both sides. When attached around a rope, the extensions 14 are crimped to generate hoop stress within the band, which compresses the band against the surface of the rope. The wall thickness of the band depends on the material used, but is typically about 2 mm.
[0014] The collar 16 shown in FIG. 3B is a solid metal band. When attached to a rope, the collar is swaged to compress and clamp the rope as described above with reference to FIG. 1. The wall thickness before swaging is about 2 mm. The collar 18 in FIG. 3C is a length of metal strip having tags 20 at both ends. When attached around a rope, the tags are brought together and secured, for example by welding, to generate hoop stress that compresses the band against the rope surface. The collar shown in FIG. 3D is in the form of two matching or complementary tubular portions 22 and 24. The engagement or abutment surfaces 26, 28 are joined or clinched together when swaged to maintain the required pressure against the rope. Regardless of the form of collar used, the resulting inward pressure on the rope is in the range of 5 to 8 tons. The collar in FIG. 3E has two matching halves 30 that interconnect as shown and can be crimped as shown at 32. The halves 30 can be brought together around the rope and interconnected, and after crimping, swaging can be performed to achieve the desired inward pressure on the rope.
[0015] The rope 34 in FIG. 4 is shown having a tubular element 36 around it between adjacent collars 38. The element 36 is not fixed or secured onto the rope and can move along the rope between adjacent collars. Each element 36 is a single band similar to that shown in FIG. 3B but has a curved outer surface. The adjacent collars 38 have matching annular recesses (not shown) at their juxtaposed ends that, when brought together, receive the ends on the element 36. In a preferred embodiment, the element is compressible and substantially fills the space between the collars so that the collars and element together serve as a sleeve for the rope.
[0016] FIG. 5 is a view showing a safety device in the form of a lockable ring suitable for locking a bicycle or motorcycle. The device has a rope of the above-described type within a protective sleeve 40 (in addition to the color and optional tubular element). Locking units 42, 44 are non-rotatably attached to each end of the rope and are selectively held within a mechanism 46 so as to prevent their relative rotation.
Claims
1. A safety device comprising a flexible metal rope having a diameter in the range of 10 to 25 mm, said flexible metal rope comprising helically wound strands and having collars that clamp the rope at spaced positions along the rope, said spacing being less than or equal to the rope diameter, each collar having a wall thickness in the range of 5 to 15% of the rope diameter and engaging the rope with sufficient pressure to prevent substantial relative lateral movement of the strands at each position.
2. The safety device according to claim 1, wherein each collar is a metal band fixed around the rope.
3. The safety device according to claim 2, wherein each collar is swaged to engage the rope with sufficient pressure.
4. The safety device according to claim 3, wherein the outer cross-section of each collar is polygonal.
5. The safety device according to claim 2, wherein each metal band forms a closed loop having at least one lateral expansion portion crimped around the rope to expand the band.
6. The safety device according to claim 2, wherein each metal band is a metal strip whose ends are drawn together around the rope to expand the band.
7. The safety device according to any one of claims 1 to 6, wherein the collar engages the rope with a pressure in the range of 5 to 8 tons.
8. The safety device according to any one of claims 1 to 7, wherein the rope is a compressed wire rope.
9. The safety device according to any one of claims 1 to 8, wherein the length of each collar is less than or equal to the rope diameter.
10. The safety device according to any one of claims 1 to 9, wherein the rope strands are wound around a helically wound core.
11. The safety device according to any one of claims 1 to 10, comprising a tubular element around the rope between the collars.
12. The safety device according to claim 11, wherein the element ends are shaped to receive the collars, and both the collars and the element ends are curved to allow limited bending of the rope adjacent to each collar.
13. The safety device according to claim 11, wherein the element is compressible.
14. The safety device according to any one of claims 1 to 13, wherein the rope is enclosed within a sleeve.
15. The sleeve according to claim 14, the sleeve comprising individual elements spaced proximally along the rope.
16. The device according to any one of claims 1 to 15, wherein complementary locking units are coupled to respective ends of the rope.
17. The locking unit according to claim 16, wherein the locking unit is attached to the rope end, is non-rotatable relative to the rope end, and is adapted to engage to prevent relative rotation between the locking unit and the rope end.
18. A method of making a metal rope for use in an apparatus according to any one of claims 1 to 17, wherein a metal collar is disposed on the rope and swaged to engage the rope strands with sufficient pressure.
19. The method according to claim 18, wherein each collar is in the form of a ring.
20. The method according to claim 18, wherein each collar is disposed on the rope in the form of complementary tube portions of substantially semi-circular cross-section.
21. The method according to any one of claims 18 to 20, wherein as a result of the swaging of the collar, the outer cross-section of the collar becomes polygonal.
22. The method according to any one of claims 18 to 21, wherein the swaging reduces the diameter of the rope by an amount within the range of 6 to 8%.