Fixed device

Abstract

The fixing device has an elongated body made of metal, at least one end of which is attachable to the locking unit. The body has at least one track of the above-mentioned type of material extending longitudinally on the surface of the body and metallurgically bonded thereto. The material of the track has particles of a hard, cut-resistant material dispersed in a self-adhesive matrix with a melting point lower than that of the body, the material further comprising one of nickel, iron and cobalt, with a composition including chromium, silicon and boron. The track is usually applied to the elongated body by welding, preferably laser welding or laser cladding, although plasma arc welding or brazing may also be used. The low melting point prevents melting of the elongated body while allowing for metallurgical bonding. Tungsten carbide is the preferred hard, cut-resistant material, although other materials may be used, such as silicon carbide, cubic boron nitride, or industrial or synthetic diamond.

Description

Technical Field

[0001] The present invention relates to a fixing device, and more particularly to the use of a cut-resistant material in an elongated element that forms an essential component of the fixing device. The object of the present invention is to provide an element that is extremely difficult to cut, and thus prevents or inhibits a device fixed by the element from being destroyed by a thief. The present invention particularly relates to a fixing device in which at least one end of an elongated body is attachable to a locking unit.

Background Art

[0002] Examples of well-known cut-resistant materials are cermets, tungsten carbide, titanium carbide, titanium nitride, and titanium carbonitride. It is known to use materials such as tungsten carbide to form a wear-resistant layer on the surface. Such a layer can be formed by flame spraying and / or laser cladding. Typically, tungsten carbide particles are dispersed in a self-fluxing matrix or alloy based on nickel, iron or cobalt of a composition containing chromium, silicon and boron, as discussed in the conference paper "High temperature erosion wear of cermet particles reinforced self-fluxing alloy matrix HVOF sprayed coatings" published in Materials Science in September 2015. Products having such a layer or coating are available from various companies such as ASB Industries Inc. in Barberton, Ohio, USA, B&B Precision Engineering of Huddesfield in the UK, and Oelikon Metco of Pfaffikon in Switzerland.

[0003] See the descriptions of Patent Document 1 and Patent Document 2, and Patent Document 3, and Patent Document 4, Patent Document 5, and Patent Document 6, all of which disclose the use of tungsten carbide in an alloy matrix. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent No. 4136230 [Patent Document 2] U.S. Patent No. 4561272 [Patent Document 3] U.S. Patent Application Publication No. 2005 / 0092038 [Patent Document 4] European Patent Application Publication No. 2740553 [Patent Document 5] European Patent Application Publication No. 2808107 [Patent Document 6] European Patent Application Publication No. 3974552 [Overview of the project]

[0005] The present invention relates to the concept of reinforcing the working components of a locking device with a cut-resistant material. According to the present invention, the locking device has an elongated metallic body, at least one end of which is attachable to a locking unit. The body has at least one track of the above-mentioned material that extends longitudinally on the surface of the body and is metallurgically joined to the body. The material of the track has particles of a hard cut-resistant material dispersed in a self-fusing matrix having a melting point lower than the melting point of the body, and further containing one of nickel, iron, and cobalt in a composition containing chromium, silicon, and boron. The track is usually applied to the elongated body by welding, preferably laser welding or laser cladding, but plasma arc welding or brazing may also be used. The low melting point prevents melting of the elongated body while allowing for metallurgical joining. Tungsten carbide is a preferred hard cut-resistant material, but other materials such as silicon carbide, cubic boron nitride, or industrial or synthetic diamond may be used.

[0006] The preferred matrix used in the track material of the device of the present invention is, ideally, nickel or cobalt-based with a hardness of about 50-60 HRC (Rockwell C hardness). A particularly preferred matrix is ​​nickel-based, optionally containing iron. In the matrix forming the track of the element of the present invention, the hardness of the cut-resistant particles is preferably in the range of 2500 to 3000 Hv (Vickers hardness), and the hardness of the matrix is ​​in the range of 500 to 600 Hv.

[0007] The base material of the elongated body is usually steel, typically low-carbon hardened steel. A preferred material is a low-carbon steel surface hardened to 58-60 HRC.

[0008] The matrix, having dispersed particles, can be in solid or powder form. In solid form, it is dispensed as a rod or wire that must be melted when the track is applied. This generates a lot of heat in the application area, resulting in the body material moving into the track. A preferred application process is to use the powder form and dispense it directly into the body to weld and form the track. The movement of the elongated body material into the matrix should be kept to a minimum, preferably less than 10% of the volume of the track material.

[0009] The particles in the matrix forming the tracks of the elements of the present invention are preferably spherical in shape, with a typical size variation in the range of 50 to 160 μm. The particles can also be cast and crushed in shape. In this form, the dimensions of the particles typically vary between 50 and 200 μm. In some embodiments, mixtures of spherical and crushed particles can also be used. The particle size variation determines the density of particles in the matrix, but particles that are too small may melt or collapse when the track is applied to the body, and particles that are too large may not be retained. The particles typically make up 40 to 65% of the volume of the track material.

[0010] In most embodiments of the present invention, several separate tracks, typically three or four, extend across the surface of the body. However, in certain embodiments, the tracks extend adjacently and side by side to completely cladd the body. In other embodiments, the tracks may be applied in different directions so as to intersect each other on the surface of the elongated body. In some embodiments, after one or more tracks have been applied, one or more tracks can be compressed into the body to substantially re-establish its original cross-section. At one or more ends of the body to be received by the locking unit, this compression can be limited to each end section. One or more tracks typically extend along the entire length of the elongated body, but can terminate before one end of the body or before each end, leaving the end sections for reception into the opening of the corresponding cross-section of the locking unit.

[0011] In the device according to the present invention, one or more tracks of an elongated body and similar tracks of the same material may be applied to the locking unit. In particular, if the end of the body is fitted into the opening of the unit, the tracks of the material may be metallurgically joined to the locking unit around the boundary of the opening.

[0012] The dimensions of the tracks on the elongated body or each track in the elements of the present invention vary depending on the dimensions of the respective body. However, for a body with a circular cross-section having a maximum diameter of 5 cm, the typical maximum track thickness is 2 mm or less, preferably 1 mm or less, and the typical width is in the range of 3 to 10 mm.

[0013] In all embodiments of the present invention, the final product may be plated, coated, or encapsulated in a polymer material, preferably a low-pressure plant-based polymer, to provide corrosion resistance and long service life, and to alter the position and pattern of the reinforcing tracks.

[0014] The device of the present invention can be used in various portable fixing devices such as bicycle locks and motorcycle locks, for example, padlocks, D-locks or U-locks of the types described in European Patent Nos. 3193405 and 3584394, and door locks, safes, and catalytic converter locks given as examples for many other applications.

[0015] The present invention also relates to a method of reinforcing an elongated metal body of the type described herein by welding at least one track of a material containing particles of tungsten carbide or other hard, wear-resistant or cutting-resistant materials described herein, suspended in a low-melting-point self-fusing metal matrix.

[0016] Here, the present invention will be described by way of example with reference to the accompanying schematic drawings.

Brief Description of the Drawings

[0017] [Figure 1] It is a perspective view of the lock portion of a device including a fixing element according to the present invention. [Figure 2] It is a view showing the form of tungsten carbide dispersed in the matrix in track 8 of FIG. 1. [Figure 3] It is a view showing the form of tungsten carbide dispersed in the matrix in track 8 of FIG. 1. [Figure 4] It is a perspective view of an elongated body embodying the present invention. [Figure 5] It is a cross-sectional view of an elongated body embodying the present invention. [Figure 6] It is a view showing how the present invention can be used in a product. [Figure 7] It is a view showing how the present invention can be used in a product. [Figure 8] It is a microscopic photograph view showing a cross-section of a track joined to a fixing element in the device of the present invention.

Modes for Carrying Out the Invention

[0018] Figure 1 shows two housing members 2A and 2B fixed to each other by an elongated fixing element 4. The element 4 consists of a solid metal, typically a steel bar 6 to which a track 8 is welded. The material of the track includes a hard cut-resistant material such as tungsten carbide in a low melting point self-fusing matrix or alloy of the type described above. At one end, the element 4 is mounted in a slot 10 of the housing member 2A in order to pivot about a shaft 12 fixed within the member 2A. The other end of the element is received in a slot 14 that is held by a locking mechanism (not shown) operated by a removable key 16. With the bar fixed in position as shown, there is little space between the bar and the base of the recess, and the bar crosses a recess defined between the housing members 2. Since this space cannot be accessed by any conventional cutting mechanism, the underside of the bar 2 as shown is protected by the housing members 2. When the other end of the bar is released by the locking mechanism, the bar can pivot clockwise as shown to separate the housing members. Of course, the locking mechanism operates to simply remove the bar end from the housing member 2B and allows it to be pulled directly out of the slot 14, in which case the bar can be fixed and attached to the housing member 2A.

[0019] The self-fusing matrix is nickel-based combined with chromium, silicon and boron. A preferred composition is 15% chromium, 3% boron, 4.5% silicon, 0.65% carbon, and 3% iron, the remainder being nickel, although some ceramics are also usually included.

[0020] Figure 2 shows spherical tungsten carbide (WC) particles dispersed in a nickel-based matrix of the type shown in Figure 1. The dispersion is random, with smaller particles tending to occupy the spaces between larger particles. Particle size varies in the range of 50–160 μm in diameter. The matrix is ​​nickel-based and contains silicon and boron. A composite of such particles in this matrix is ​​available from Stoody Industrial Welding Supply, Inc. in San Diego, California, USA. The WC particle content in the matrix is ​​approximately 65% ​​by volume. Figure 3 shows cast and crushed WC particles in the same nickel-based matrix as in Figure 2. As can be seen, the particle density is approximately 80% higher than that in Figure 2.

[0021] Figure 1 shows an elongated fixed element with a substantially square cross-section, but any suitable cross-section can be adopted. A single track 8 may be duplicated on one or more other sides of a body having a polygonal cross-section, but the present invention is usually embodied in elements in the form of an elongated body with a circular cross-section. Figure 4 shows examples of tracks being applied to different solids in different patterns, four having one, four, six, or eight linear tracks, and three having four, six, or eight helical tracks. A cross-section of a similar body is shown in Figure 5. As can be seen, it is possible to apply tracks very close to each other, practically adjacent, or overlapping with the body and completely cladding it.

[0022] As described above, in the device of the present invention, one or more tracks applied to an elongated body can be compressed within the body to substantially re-establish the original cross-section of the body. The advantage of this is that the position of the tracks can be obscured or hidden. Another advantage is that the tracks can extend to one or both ends of the body and be received by a lock or other unit designed to accept the original body shape.

[0023] The present invention can be suitably embodied in well-known fastening devices. One such device is the D-lock or U-lock commonly used on bicycles and motorcycles. Figure 6 shows how a “D” or “U” section 20 can be reinforced by the application of tracks 22 welded thereto, as described above. In the illustrated reinforcement, the tracks terminate just before the end of the section, allowing the end to be received into an opening in the locking rod 24 of the original product, which has the same cross-section as the unreinforced section. The rod itself may also be reinforced by one or more tracks 26. In a preferred feature applicable to all embodiments of the present invention, additional tracks 28 can be welded around the point where the section end is received into the rod or locking unit. Of course, if the tracks 22 are compressed within the section 20, they can extend to the end and into the locking rod 24. It will then be understood that the present invention can be retrospectively applied to existing products.

[0024] Another well-known fastening device that can be enhanced using the present invention is a padlock. As shown in Figure 7, a matrix track 30 having distributed WC can be welded to the padlock body 32 in addition to a track 34 welded to the shackle 36.

[0025] The micrograph shown in Figure 8 illustrates the bonding between the track 38 and the elongated element or body 40 in the device of the present invention, minimizing the movement of the track material into the body material. As can be seen, tungsten carbide particles of various sizes (shown in white) are distributed in a self-fusing matrix or alloy (shown in gray) that, upon application, displaces a portion of the body material due to either compression or softening of the material during the application process. The particle distribution is random, but the concentration is clearly sufficient to ensure resistance to any attempt to cut.

Claims

1. A fixing device comprising an elongated metal body having at least one end attachable to a locking unit, wherein the body has an original cross-section that is square, circular, or polygonal, and at least one track extending longitudinally on the surface of the body having the original cross-section, the material of the track having particles of a hard, cut-resistant material containing nickel, iron, and cobalt in a composition containing chromium, silicon, and boron, dispersed in a self-fusing matrix having a melting point lower than the melting point of the body, and the track or each track being metallurgically joined to the elongated body.

2. The fixing device according to claim 1, wherein the material of the cut-resistant particles includes at least one of tungsten carbide, silicon carbide, and industrial or synthetic diamond.

3. The fixing device according to claim 1, wherein the cut-resistant particles are in a spherical shape.

4. The stationary device according to claim 3, wherein the size of the particles varies in the range of 50 to 160 μm.

5. The fixing device according to claim 1, wherein the particles are in a cast and crushed form.

6. The stationary device according to claim 5, wherein the dimensions of the particles vary between 50 and 200 μm.

7. The fixing device according to claim 1, wherein the particles comprise 40 to 65% of the track material.

8. The fixing device according to claim 1, wherein multiple tracks are arranged adjacent to each other in the circumferential direction of the main body so as to completely cover the main body.

9. The fixing device according to claim 1, wherein a plurality of the tracks intersect each other on the surface of the elongated body.

10. The fixing device according to claim 1, wherein the at least one track has a maximum thickness of 2 mm.

11. The fixing device according to claim 1, wherein the at least one track has a width in the range of 3 to 10 mm.

12. The fixing device according to claim 1, wherein the at least one track is compressed within the elongated body.

13. The fixing device according to claim 1, wherein the elongated body has a circular cross-section.

14. The fastening device according to claim 1, wherein at least one end of the elongated body is attachable to the locking unit by entering an opening therein, and a track of material having particles of a hard, cut-resistant material dispersed in a self-fusing matrix containing nickel, iron, and cobalt in a composition containing chromium, silicon, and boron is metallurgically bonded to the locking unit around the boundary of the opening.

15. The fixing device according to claim 14, wherein the material of the cut-resistant particles in the track around the opening includes at least one of tungsten carbide, silicon carbide, and industrial or synthetic diamond.

16. The fixing device according to claim 1, wherein the elongated body is enclosed within a layer of polymer material.

17. A padlock comprising the fixing device described in claim 1, The aforementioned elongated element is a padlock shackle.

18. A D-lock comprising the fixing device according to claim 1, wherein each end of the element is adapted to engage with a locking rod.

19. A method for reinforcing an elongated metal body having an original cross-section of a square, circular or polygon by welding at least one track of cut-resistant material extending longitudinally on the body to the surface of the body having the original cross-section, wherein the material of each track has particles of a hard cut-resistant material comprising nickel, iron and cobalt, with a composition comprising chromium, silicon and boron, dispersed in a self-fusing matrix having a melting point lower than the melting point of the body, and the track or each track is metallurgically joined to the elongated body.

20. The method according to claim 19, wherein the elongated body is part of an existing fixed device.

21. The method according to claim 19, wherein the material of the track is joined to the surface of the body by laser welding and laser cladding.

22. The method according to claim 21, wherein the matrix comprises a ceramic material.

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